This is the content that makes your channel the best Ronny. Honest and trustworthy. No hype. Thanks again from a guy who makes his living from his trusty Landruiser 70.
i have broken 3 short shafts on my 80 in the past 8 years with no damage to the center, was thinking about changing to chromemoly ones but now i think i'll just keep a spare shorty for just in case, seams they are the sacrificial part to keep the rest safe and easier and cheaper to change than the diff itself. thanks Ronny
Sir, that's the correct way to do it. Pack along the right gear oil, hand cleaner, rags, and your favorite bottle of 'assembly lube.' I prefer a shot of good whiskey.
When your truck keeps breaking short shafts, it’s trying to tell you something. Too much HP is pushing too much weight. Reduce one or both and keep your machine running!
I'm not surprised at all Ronny. It's simple physics. Your cruiser carries a lot of weight, the bigger tyres, most of its life it's 4 wheeling in the bush somewhere with the lockers engaged adding more stress to the driveline. Something will give. I've been a mechanic for 20 years and i currently work at Toyota and i understand the GVM upgrades that yourself and others make to these 79's. Unfortunately the vehicle isn't designed to handle the extra weight even with the GVM upgrade, as the upgrade is only on the chassis and suspension and not the driveline. Another thing, the Toyota steel axles twist more as you said because they're softer so it'll take more for them to break. Chrome Moly doesn't flex as much so it's more brittle and will snap quicker under excessive loads. Toyota are smart making their axles the way they do like a "fuse" in the system. Like you said better to break at the outside end than the inside taking the diff centre with it. I'd rather break a Toyota axle and have a spare and be on my way in the bush rather than a Chrome Moly one. I applaud you for making videos like this to educate people about components and the honesty that goes into it. Fantastic and very rare! That's why you're number 1 mate!! Well done! Love your work! Go the 79.
Makes sense but....Toyota opted to not increase the width of the rear axle for the purpose of saving $ when they dropped the V8 up front. As far as i know all the after market solutions to increase the rear track utilise chrome moly. If only the Toyo factory could produce the VDJ with matching tracks there wouldn't be a need to source these parts. There lies the conundrum
@@cyclemoto8744 there is absolutely no need to increase the rear track width of the 79 series landcruiser unless you do a lot of sand driving. The compromise on capability is negligible on all other surfaces. But everyone's jumping on this like it's a major problem. It's not. If it was, Toyota would have reworked it. My brand new 79 arrives next week and I won't be touching the rear axle. It's a bloody capable vehicle the way it is. If you must correct the rear track, use offset rear wheels. Another thing I don't like about the aftermarket rear axles is the stepped welded plates that form the diff pumpkin. This stepped shape behind the crown wheel greatly affects the splash dynamics of the diff oil being thrown up the rear of the diff housing and over to the front where the pinion is. This shape is critical which is why all diff housings on the planet have a smooth round shape. You'd be surprised the difference it makes to oil flow.
Are you sure this is the case with the Dana axle available for the 70? With regard to the track, in my opinion the drivability is affected when towing, not just with sand driving. I have personally used a wheel offset ( NOT WHEEL SPACERS) to address the issue somewhat
@@cyclemoto8744 of course I cannot be sure that this is an issue with the Dana axle for the 70 but I'm very sceptical of it as I understand how diffs work. It may reduce service life of the internals if it's not oiling them properly. Was this sufficiently tested by them? I don't know. Have you had bad experiences towing with the stock track width? I think using the offset wheels is the way to go.
I acquired the vehicle when it was in stock form so I have experienced both the standard and increased track. I agree with you that there are many unknowns when choosing to go down the path of an aftermarket diff housing to widen the rear track (off set wheels generally only create premature wear on the bearings). Ronny's video has certainly highlighted the cons: unlike the Toyo short shaft the point of failure on the chrome moly shaft resulted in the diff being damaged. That being said, as stated by others, had the car been towed away instead of driven, the diff may not have incurred any damage. In any case, in this particular situation & location, the expense of the repair (or towing if that had been chosen) resulted in a greater cost when compared to the damage a genuine shaft would have created (in theory of course).
So with the JMAX short half axle breaking and, all the load for everything on the JMAX long half axle it was still strong enough to get you home over 3,000 km? Overall, the vehicle could still be moved under its own power and you got home alive. Given the scenario conditions I'd be going out and buying a Lotto ticket. Thank you very much for the video. Not many would have bothered to give us such a great explanation in plain language. Also thanks to PDP for supporting you (great guys), and JMAX for being honest in a field of manufactures that are not.
I’m a mechanical engineer so I have some understanding of this. That helical fracture surface is a classic torsional stress failure. It also failed near/at the spline which is an area of stress concentrations, due to the machining of the splines. This appears to be a classic fatigue failure, whereby a fracture initiated and propagates from a stress concentration and the crack grows and grows and then eventually let’s go simply because there is no meat left in it. This is visually characterised by ‘beach’ marks at the crack followed by a rough or crystalline surface appearance when the shaft finally let’s go in a brittle manner. Bloody hard to diagnose that if you’ve driven it for so long after the failure as most of those tell tale signs get ground away in the subsequent damage. Hope this added something.
@@rgals2231 Im a metallurgical engineer. The concept of weak and strong metals is only a partial insight into the properties. What really counts in shafts is toughness, and that is the area under the stress-strain curve. Toyota has the metallurgy nailed, rest assured. The others just dont have the resources to optimise the metallurgy. Consider the difference between a copper shaft and a glass shaft. The glass shaft is much stronger in tension or torque, but it has very limited toughness. If there is a stress concentrator in the glass shaft, such as splines, it will fail spectacularly in a brittle manner (with or without fatigue loadings). I have personally broken 3 rear aftermarket diff shafts, on my landcruiser with arb locker. I have since gone back to original toyota parts, and havent had any further issues. But a big part is to find a high level machinist type knowledgeable installer, who uses blueing to line up the crownwheel and backlash, not just slap it together like some mechanics do.
Nothing is unbreakable. Everything has its safe working load. When you Mod cars, ask for more power, more torque, add more weight, bigger wheels, something is going to fail, if pushed hard enough. That is the price of admission. Well Done, great video.... I'd have also thought, as metals get "Harder" they also become more brittle. Hence why we don't have Tungsten Carbide axels.... I wonder if you can make a sacrificial sheer point at the hub end (not in the shaft but on the end plate) that is easily replaceable on the tracks? Either that or its time for a sheet metal diff to house a 9" with 36 spline, 4340 larger diameter axels.
The amount of torque load that an axle can be subjected to can be estimated by taking the engine torque, multiplying that by the transmission's first gear, and the again by the rear end ratio. Im not sure how you equate the weight of vehicle into this, but im sure it can be done
Actually, Nissan Pathfinders (at least circa 95 or so) have this on the front hubs. This is kind of 'built in' on the older rigs with 2-piece axles - you'll typically shear the splines or keys before you blow a diff or t-case. I run stock axles on my '48 Willys CJ just for this. It's easier to replace an axle or hub on the trail than to get out with a blown diff.
@@benwinter2420 I posted on this - Look at the mods he's done over the last year. Suspension, tires, engine tune, added weight, but he hasn't changed his driving style. All of his mods increase traction, but he still uses 4x4 and lockers frequently. He _used_ to need them in those scenarios, but not any more. You can't drive a full-time 4x4 system in a 'perfect traction' scenario without a failure. When you bind it up, something has to give. If a tire won't slip, then something expensive _will_ break. The mods add up to make more situations a 'perfect traction' scenario.
Exactly, he went over the specs the rear axle was designed in the first place and it broke; now you have 2 options: upgrade to a heavier duty axle (if you want to keep the rig like it is now and with the same driving style) OR make your rig lighter, smaller tires, easy on the skinny pedal, etc and keep the stock OEM axle.. not much you can do besides that
@@yepitsme431 spot on - make the rig lighter. So the question is how? Ronnie's been working on a lighter rear storage system, so that will help. I also wonder if he could switch to a minimalist (perhaps aluminium?) tray - just enough tray to carry the gear he's got. The new storage system also appears to shift some weight further forward which will help with distributing loads on the drive train, so with the front wheel in the air scenario, this will allow the rear to break traction a little sooner, perhaps saving a shaft. You gotta admit - Ronnie's got his rig tuned pretty optimally.
considering what you do to bring us these videos and towing a trailer, i am not really surprised you broke a half shaft. it doesn't matter how strong it is the shock loads can be extreme. thanks for all the great content.
Awesome conclusion to the series. Thank you for following up with all the explanations and cudos to the manufacturer for providing all that information.
I think having the shaft as a fuse of sorts in the drive line is good. Granted, I know you were away from home base and may not have been equipped to open up the diff. Had you been able to open the diff trackside prior to the 3000km even just to get the crunchy bits out it may have saved the diff center (big maybe). As your experience/research has revealed both axle types are suceptible, in your configuration. Props to Jmacx for being upfront and taking the oppurtunity to share some knowledge. I think overall it would give me more confidence in their product. Thanks to you for sharing your experience with us, sorry for the hit to your wallet.
Well, thanks for educating those of us that haven’t previously considered the related mechanical stresses caused by installing larger tyres, performance upgrades and carrying extra weight.Yes, I will now be more mindful of the more realistic limitations/expectations I have of my own 4x4 after your costly experience. I appreciated the way in which you informed yourself about the different factors involved that can come together and cause such an annoying and trip ending mechanical break down. Many thanks for sharing your experiences and knowledge with us.
I really appreciate the unbiased way you put this video together. I see way to often people jumping to conclusions without all the info. As usual you don't disappoint. Good work! I used to wheel a Full size Chevy Blazer and it too had a narrower width rear axle and the explanation i received at the time was that it decreased the chance of rollover during high speed maneuvers...safety rating or something of the sort. Also found it very annoying. In regards to your snapped shaft, having a weak point in the system can be beneficial. just keep spares and the appropriate tools onboard to repair on the trail. Although i too would've thought the 3rd member in this particular case would most likely be the fail point. Toyota certainly didn't make it very easy to investigate the diff, too bad pretty sweet machine otherwise. Your rig is certainly an awesome build and i look forward to all your content to come! Love every minute of it, It's a great contrast to my world of Canada, Cheers!!!
I don’t know much about this stuff, but your presentation was fantastic. I totally get it now, I do many presentations for work, you nailed, great job, love your vids!
Great work, Ronny. No rubbish, no fluff, just plain honest facts. It’s also great to see JMACX standing behind their own product and being so open about the failure rate which really is bugger all. PS: what happened to the great Ronny shave day????
Hi Ronny, as usual great and informative, keep up the exceptional job and ill keep paying Patreon, such a pleasure to see inpartial information, and the 79 is a great truck I love mine and look forward to catching up with you sometime in the future
Honest review Ronny. This is what makes your channel. Definitely surprised about jmax but more intregity for a company like that who responded so professionally. Big ups mate
Hi Ronny , looks like I'm not the only one to test to limits. I took out the short side and ashcroft diff on my 4.6 Range Rover HSE going from Ice to rocks in Europe trip. 1900 mile back to home in 2 wheel drive. I unbolted prop shaft from transfer to rear to continue home.
I think you guys just figured out the limits of the equipment. Considering the mods, the weight of all your stuff and the conditions of the terrain you're going through, it is definitely impressing what these cars can handle! Adding up the hours of "punishment", it just has to happen one day, as even the strongest parts wear out.
Over equip and underload. Equip heavy and load light. That shaft would have held if you were just on a paved flat highway, but the incline and sudden pull was what became the proverbial straw that broke the camels back. Safe travels always to you Ronny and your mates.
Good video Ronny. I'm also overloaded for my ram 1500 and rear axel has concerned me and you illustrated for me exactly what and how all this stress can come to breaking point. cheers from canada
Love your videos Ronny, and your Flinders Ranges 6 Part was awesome. I also took the time to watch your Broken axle video which was very informative and I wish to offer one additional point to consider which is the use of diff lockers, axle wind-up and subsequent potential metal fatigue to related components. As you know once the diff/diffs are locked they create a solid driveline by removing any slippage through the least path of resistance. So once the diff is locked all torsional energy is transferred directly into the many, many related driveline components. Wear and tear aside, driveline component failures and fatigue issues generally arise once the torsional stress of a component is "exceeded" and when this happens the component will either break immediately or start single or multiple stress fracture which over time the fractures/stress points will continue to fatigue and over use and time will eventually fail which appears to have happened in the axle splines in your case. A simple explanation of this this is if you take a pieces of light metal and continually bend it eventually it will weaken and break, this is what also occurs in a drivelines. In drivelines torsional stresses are dramatically increased when the diff locks are engaged on hard surfaces and are compounded by loads, shock loads and all the other factors you mentioned, i.e. bigger wheels, engine chipping etc. which increase the torsional stresses so the careful and limited use of diff locks as an aid I think is important for component durability and reliability. I don't have actually have evidence, but I think it's a fair bet that Toyota would have intentionally engineered their axles to 1. fail on the outer and limit consequential damage, 2. limit catastrophic damage elsewhere and 3. make relatively easy to repair. There are many many factors to consider as serious 4X4 will always push the boundaries and test the limits of people and their equipment, be safe! Your Diff locker Video ua-cam.com/video/4U1SLSV9wNk/v-deo.html Once again thank you and keep up the great work, StanM
They should machine a shallow ring groove around the circumference of the axle, near the hub end, a fail point, should the axle be overstressed. Yes, it will weaken the axle slightly however, it may save the diff and make it easier to pull the center section. It would still be MUCH stronger than the factory Toyota axle.
Hi Ronny,I think in your case the Dana 60 full floating axle would be the way to go. There is one available for your cruiser. It seems a much stronger assembly compared with the Toyota axle assembly. Stronger splines etc.
Hi Ronny great video thank you for sharing the only thing I can add is that if at any stage your Lockers are engaged and there is solid ground you put the side shafts under the torque that will weaken or snap the shaft. So I would think this happened in the past, which was the route of your problem.
Thank you Ronny for another excellent video. What evidence do we have to prove that JMAX is stronger than Toyota? This is an unique opportunity to send reminders of both axels to a laboratory and get them destructively tested for the maximum torsional load.
That was very informative Ronny. I guess the other big factor in the failure at the time, was the fact you were towing that camper trailer up such a steep track. Sorry it happened to you but it was great you shared the info.
My favorite mechanical fuse is the hub. Warn had a hub kit for Jeep CJ's with notoriously week rear outer splines. They converted to FF and had the same manual hubs on all corners. It probably wouldn't haul much more, but moving hubs around to keep going would be a small chore.
I am glad you quoted the extra load the 35 inch wheels cause on the drive line I have been saying that for years you are lucky to have a car with a low range geared to handle them but are pushing the limits with the mechanical components , great video regards mike
I follow Jmaxc especially since they're a Sunshine Coast, QLD based company. Jason form Jmacx has stated in videos that the chrome molly axles have broken before and the majority was due to extream use/mods. Furthermore, he has developed a 300M 32 spline axel which is even stronger than chrome molly. Was I surprised it broke no because until you pull it apart you just don't know? Also, Ronny, you've got to remember it's a company vehicle which you use what 80-90% off road under all these loads. The more off-road driving you do the more likely things are going to break. If you're going to spend the coin you may as well put the 300M axel in. Jmacx has always been open and honest about their products. Another good honest Aussie company.
Not surprised it happened. While you look after your gear, considering the miles you travel, loads carried etc it was inevitable at some point that something was going to break and will again some day. And it's always going to be the weakest link. The use of diff locks is a tricky topic. If I'm locking in, I always lock front any back and try going as slow as I can at first, increasing momentum after each attempt if required. I even unlock the diffs if I need to try a high speed/momentum drive on an obstacle. My thinking is that the open diff will handle the shock loading a little better and not torture the driveline components quite so much when lifted wheels come down etc. Doesn't always work, sometimes I need to drive hard when locked. Great explanation on the Jmac product. I haven't got one, but still believe it's the only way to correct the track, and the axels are no weaker than the original Toyota equipment. Great work Ronny👍🍺
This is the reason I stayed with stock shafts on my jku. For my peace of mind I carry spare shafts and keep the "fuse" as the axle shafts because that can be changed on the trail and its alot cheaper then a diff.
DANA 60 time Ronnie!! Thanks for sharing it too! IMHO you’re operating the vehicle beyond its designed capabilities. I know you know this. Can you lighten your vehicle more? I can’t believe how much stuff you guys take. All the % stats from Jason should ring some alarm bells. Good luck with the repair
Good explanation Ronny in real terms. I could go into some serious details about modulus of elasticity but basically you nailed it stating the axle will have gone beyond it's elastic point previous to the point it blew out. It's unfortunately just one of those things that happen when we run our vehicles heavy constantly & well beyond 'normal' limits, painful to the wallet as that may be. I'm glad you mentioned at the end it wasn't the fault of the components as it's very easy to lose your sh*t & blame the manufacturer when in reality we all push our gear to beyond the maximum. For a non serious suggestion, fit Nissan axles & you'll be good😜* *apart from it completely ruining the awesome gear reduction you get on a Cruiser (nothings perfect)
Tings are designed stock for a reason. Manufacturers don't make parts weaker for no reason. It's usually to save something more crucial and expensive. As soon as you go non stock there will be occasional problems when parts are under load, so learn to live with it. Ive got a stock Navara D22 that has taken men everywhere I need to go (some very tough stuff too). All I've added is a snorkel, bash plates, and better shocks. Best forby I've ever had as reliable and tough as nails. Its all about how you drive after all....
Many years ago when i used to drag race we would paint a line the full length of the axle so we could track how much twist was in the axle and whether it should be replaced. For Jmax 6 in 1400 axles is not a significant failure rate and from an engineering perspective does not warrant design change, but it would be possible to design a drive flange that failed before the axle. Just like on the 60's and early 80's the smaller drive flange bolts used to shear. Now we have 10mm studs the axle tends to break first
Fantastic video! There could have been a metallurgical defect within the shaft. The only way to find these defects are using Non Destructive Testing methods during the manufacturing processes like xray or ultrasound. I recommend that the manufacturer implement these inspection methods during manufacturing. The cost would be insignificant relatively speaking.
I can add an interesting sequel to this story. One of my customers whose rally car we are currently working on snapped the 13th (or 14th, he couldn't remember) Jmacx axle on his 70 in February 2020. His complete kit had been bought in October 2017. We've been using the same axle supplier as Jmacx for many years and their stuff is excellent. Unfortunately nothing is indestructible Ronny. The best axle builder I ever knew who's since disappeared would never tell me his secret apart from 'its all in the heat treatment'. I could not argue, the national championship winning off road racing car I ran and he built the axles for never had a failure compared to constant failures of some of the biggest names in axles beforehand. BTW, can I assume they sorted you out with a warranty replacement?
thanks ronnie entertaining and informative love the channel and keep up the good work mate, Just for future reference on the off chance you blow a diff or another axle, it is a very good idea to take out the drive shaft and axels or remaining axels and driving home just on the front diff simply to stop the rear diff from rotating and grinding up chunks of steel with the teeth, both to save your remaining parts from damage eg crown wheel and spider gears, and for safety reasons if a big enough peace of steel gets jammed the diff internals can actually explode and throw the drive shafts off which at highway speeds is usually not good.
Hi Ronny - there is lots of grades of chrome moly - 4130 and 4140 being most common, these can be heat treated to any hardness, the harder they are the less maluble they are (less twist) so they have different characteristics. The chrome moly shafts should have a thinner section towards the outside so if it breaks you can change it, (I know this makes them weaker but diffs arnt cheap) also dont forget locking up a diff puts huge load on these if its hrad ground, keep up the great videos
I've read lots of trucks have narrow rear axles because this promotes under steer which is generally considered more favorable than over steer as far as driver correction probability. Just slow down to correct under steer. To correct over steer requires a steering correction (it is VERY easy to over correct, especially if you are not experienced with over steer) and most people prefer to be kept pointing straight ahead instead of the rear coming out from behind them. Just about every production vehicle is designed to under steer first at the limit. Most drivers almost never experience a lack of traction at the limit and panic is the first thing that happens so under steer is generally considered safer. I believe how this works is the wider axle has more weight transfer and this results in reaching the traction limit sooner on the axle with more weight transfer. The wider axle is a longer lever and more force from the roll of the vehicle is resisted by the wider axle. The extra force resisted is transferred to the outside tire and vehicles are designed so the front wants to skid first resulting in under steer. Concerning chromoly shafts, I've always wondered if a fully hardened shaft is what you want. Like Ronny says, you get less twist and hardened steel is more brittle. I guess it's a balancing act between ultimate strength and the axle's ability to handle shock loads. It's very convenient the stock yota shafts break at the flange. No metal bits in the center section and I suspect it's easier to change a shaft which has broken at the flange. To remove Ronny's shaft the entire center section had to come out. I'm sure the yota engineers intended for their shafts to break like that. Good engineers consider serviceability. Of course that is one of the compromises with chromoly shafts for the added ultimate strength. It all depends on your application.
I have a landrover discovery 1. 265 75r16 mudterrains. ARB air locker at back. I have broken 4 short shafys and 2 long shafts every time when i use difflock. These are all landrover shafts. You do get Ascroft chrome molly shafts which apperently does not break but you pay 6 times more for these axles. I want to try it when i have money. I am also frustrated. Nice video
Great and honest video. I’m not in the market for an upgraded rear end but anyone that is would gain a useful insight. You make the ideal guinea pig since you spend so much time off-road, pushing your gear. Tough luck with the breakage and good on you for representing jmacx in the way you did. It would be all too easy to pay out, on the compa. In light of common sense, engineering based explanations you can inform us while making a more informed decision for yourself. 👍
I agree with a few statements above. I wouldn't have spent the cash on a new aftermarket axle and just went for a Dana 60. Match gears for the front and slap in a e-locker to replace your current one. No more problems. Just my thoughts. Love the channel.
There’s an interesting video on UA-cam on the manufacture of F1 prop shafts out of carbon fibre. You should see the results of steel vs carbon fibre when used in a torque test machine - it’s phenomenally strong but phenomenally expensive! Be perfect for this job but as you quite rightly say - it’s only ever as strong as the components it fits onto! Great balanced video Ronnie. From the UK 👍🏻
Maybe check the shafts after each outing to see if their twisting/cracking? could always score a ring around the shaft on the wheel side so if it does break again it will break where you scored it, saving $$$ for another diff. I think only other option might be custom axles like a dynatrac prorock 80, but you'd have to change to 8lugs.....among other things lol
I think Ronny knows he requires 2 difficult upgrades. 1.Reduce weight. These guys carry too much crap. Too many spares. Too much water. Too many conveniences. Yea, I know, I know. I know. 2. Adjust driving style. You can’t go hard and fast ALL the time. Ask your wife …
You are the first and only person i know that broke a landcruiser diff... really these things are really really really hard to break... and u did it... who on earth u got it right i dont know but yeah 🤣 (Edit)... and how do u snap a chromaly full floating shaft?.. ronny i am really surprised... u are brutal😅😅😅
@@MrJarmore yeah... buts its a full floating shaft... i can understand if a few teeth break off the ring and pinion but twisting and snaping a full floating chromaly shaft
I think he was locked front and rear... and pulling a trailer. His rig has limited down travel so he frequently gets a tire in the air... forcing the opposite shaft to take the full load. EDIT: i guess he was only locked on front. But lifting tires, spinning then setting them down will snap stuff.
@@lumpskie yeah that's it mate. I have a very heavy 60, driving an off cambered wheel lift section. So essentially all the load was on the driver rear axle. It went bang just idling up.
Go hard or go home lol that's how I ended up with familiar problem with my JK but only thing was broken was spider gear then it worn out the crown and pinion too..
Great video. Power, tyres and weight. You have upset the magic ‘factory’ formula of reliability and strength in a Landcruiser. The engineers in Japan will be sad and disappointed that you exceeded the limits they set for us when the VDJ came out. You will now be in the ‘perpetual circle’ of pain of modification. Thanks again for the detail and research. Keep them coming. 👍
@@Ronny_Dahl Sry, was meant more as a joke, and kudos to the diff (I daily drive a 110 Lux so may be slightly toyota-biased) Thank you so much for all the awesome content, truly one of a kind, I love seeing how much you guys enjoy each others company :) Frosty greetings from Finland!
interesting how the cracking is from the sharp part of the splines groove. A classic place for a stress riser. maybe if the edges were champfered the cracks wouldnt have occured? However the twisting was still there. I like the comments for a designed in failure point
around 700 half shafts made say 15 broken i doubt every broken axle gets reported even if it was 20 that still a good ratio and the honesty from JMACX is grate its something lots of other big company's are missing these day.
I have not taken any axles apart for twenty years now but when I did I noticed that many manufacturers had ground the outboard end down a bit jus short of where the hub splines were, so that there was a deliberate breaking point. That way the dif will not get written off by shrapnel from exploding half shafts.
Ronny Dahl At 15:44 I noticed the front passenger wheel jumped up a bit as the rear shaft broke. All 3 other wheels seemed to have grip as the front drivers wheel jumped up. Wow massive transference of energy as the wheel came down thru the entire drivetrain.
As a forestry winch operator i would never advise towing wood unless you have the front of the log raised off the ground or on a sled or logging arch, incredible forces come into play when a log digs in, we have had cables snap, winch drums twist, logs flip and smashed bearing casings all from logs digging in the ground or getting caught on stumps and roots. we use a high lead system so our snatch blocks are always as high as we can place them, it can be equal to putting a strop round a healthy growing tree and driving off, somethings gonna break.
Here is the U.S. guys run Dana 60 front and Dana 80 rear axles on jeeps all the time. The 60 and 80 are off much larger full size trucks like F250 and F350s . Or guys will even run 1ton axles . Is this an option in Australia? I know you guys have strict laws when it comes to vehicle mods . Anyways Ronnie another cool video
Can you run a 60 up front and a 80 out back with the corrected withs ? I’m sure they are super expensive for your rig. You can easily spend $10,000-$20,000 for a fully built set of axle .
The same axles are available for Jeeps in Aus. There is a bolt in kit for a Dana 60 for the rear of the 70 series which also corrects track. More than that is usually not needed since it can be hard to legally run big tyres. A modified 80 series axle should be more than enough for most people, and Nissan Patrol axles are strong too which is why most comp trucks use them.
Hello Ronny I am not surprised you snapped a high tensile shaft high yield point softer steel that's why you shouldn't retension hitensile bolts the second time they fail without warning. One other thing i would consider did you damage the diff when you snapped the toyota axle and i seem to recall you fixed it in the bush. Great video as usual frank and informative.
Yep, if you keep increasing the load something will give and normally the weakest point. So what is the cost analysis between Jmax upgrade + new half shaft + new diff versus no upgrade a new Toyota half shaft and maybe carry a spare Toyota half shaft knowing it's a weak point. Excellent video and honesty is always appreciated! 👍
Interesting stuff. Oddly enough my missus reckons that your trucks diff and me share the same common problem...short shaft weakness. Sucks about the diff mate, keep up the great vids.
I don't know that there would have been an 'exact moment'. Think of these things: First, it's a full-time four wheel drive system - the type of system that shouldn't be used in a 'high-traction' situation. For a 'normal', unmodified vehicle, this typically means 'dry pavement'. This isn't for Ronnie, it's a general explanation of what's going on in a high-traction 4x4 scenario. When you drive this type of vehicle with four wheel drive engaged in a high-traction situation, it will 'load-up' or 'bind' the entire driveline. This binding is what makes it hard to take a four wheel drive vehicle out of four wheel drive. When this happens the following is _all_ happening: 1- Axle shafts (or half-shafts if you prefer) are starting to twist (I should say 'under heavy twisting loads', but I'll use 'twist' for brevity) 2- Drive shafts (or prop shafts) are starting to twist 3- shaft joints (U-joints and CVs) are being torque loaded 4- The pinion gear is starting to be forced away from the ring gear (or crown wheel) in the differentials 5- gear shafts in gear boxes are undergoing stresses that force them both apart from each other, and to try to to twist in a plane usually aligned with the ground depending on the design on of the gearbox. (These are the stresses that can cause a transmission or transfer case to crack or split open.) 6- engine and transmission mounts are being loaded in the opposite direction of torque In a 'perfect traction' situation where none of the tires can slip, one of the above components will fail. As noted by Jmacx, this failure can have a knock-on effect and damage other components. Now lets look at traction in this case: The truck has front and rear locking differentials to improve traction in less-than-ideal circumstances, such as mud, sand, gravel, etc. The truck is equipped with tires and suspension designed to maximize traction. Tires are commonly aired down to increase traction. The vehicle's high weight also increases traction. The truck has been tuned to produce more torque. Together, these modifications _increase_ the number of 'perfect traction' scenarios. This can actually increase the chances of breaking something. The operator needs to understand this and carefully choose how to set the vehicle up for a given obstacle. Something _has_ to give. If a wheel can't slip, something expensive _will_ break. Maybe not immediately, but it _will_ break. Last note: when one part fails under stress that other components may have been damaged as well. You should inspect all u-joints, axle shafts, mounts, and cases for other damage. Then pack along spare short-side shafts. Keep up the awesome trips and keep 'er shiny-side up! Les This post has been edited to remove the poster's inane remarks and uninformed commentary. My apologies Ronnie.
It is possible to make stronger axles in the same form factor. The problem is that it's simply not cost effective due to material costs etc. While chrome moly is strong there is a spectrum that starts expensive and ends in mortgage territory. en.m.wikipedia.org/wiki/41xx_steel I don't know the specifics about the jmax stuff just suggesting that there's almost always a stronger metal.. only costs or patents keep them from mere mortals.
Correct first post ive seen about this. 4130 is stronger, about twice that of factory 750mpa. I run maxi drive hy tough axles they rated at about 1100mpa which is 3 times the tensile of stock and also slightly less brittle than 4130. the best is 300m about 1600mpa this is used in high end axles and input shafts in gearboxes of high horsepower drag cars etc. Other factors in failure can be attributed to the machining of parts leading to stress risers and heat treating of materials
I hope you learnt not to screw with Toyota engineering. Toyota did everything for a solid reason. Ronnie is a massive fail as an engineer. If it was not for Toyota's engineers he would have been sitting on his behind in the bush.
a bit sad having a breakage Ronnie, but as a great man said "if you go looking for the limit, don't be surprised when you find it" maybe if you had a std clutch or an auto transmission there would be less shock load on the axles? don't machine a groove in the axle at the hub end as has been suggested below, I would taper the shaft down slightly towards the hub and polish it to eliminate stress raising ridges. BTW 4140 or 4340 are great shaft making steels in annealed condition they are not so brittle.
Thats bad luck Ronnie, but thank you for investigating fully and giving us a clear explaination. Surprised the manufacturer doesn't in-build a safe fail point into the shaft. I would have thought the OEM Toyota one does. So as a long term solution will you be carrying on the 70's weight loss diet a go down to 33"'s?
This is exaclty why i run stock. I did an fjcruiser super mods. Things broke, Toyota said “void warranty”... since then i put up with weird track, lower ground clearance etc... guess what? No drama! 😀
I have always had other 4x4 ers give me stick as my choice of 4x4 is a Landrover Defender and this make have always had a reputation of breaking axles, although I have never had this experience myself. Rightly or wrongly I believe the axle design is a deliberate weak point to reduce the possibility of additional damage to diff centres as you have shown. Axles in most cases are easier to replace or remove entirely on the track without further diff damage through rotating parts interacting with metal debris if the drive shaft is also removed. The Landrover design differs from Toyota and many others in that they are a fully floating axles front and rear meaning splines on both axle ends. This makes driving in front wheel drive to get you home in a case such as this simpler to achieve as no rotation will occur if the tail shaft is removed before any further travel.
Think I’d be going down to 33’s. That 25% extra stress for a limited advantage isn’t worth it! A lesson for us all; as another commenter said, better a weaker shaft that will shear before other parts of the drivetrain!
The Toyota OEM shaft is designed to shear at the hub... TO PROTECT THE DIFF!... screw with that and you are buying new diffs every time... some rich people!
Hi Ronny, i have an idea for you. As it stands, you upgrade almost everything on your vehicle all except the engineering in crucial parts. So as a result (short from upgrading to lorrie gearbox and axials) you wil always have this nagging feeling at the back of your mind that your axials might snap when you do the ruff stuff. How about taking off all the extra weight and make it a project to see if you can still get all your extras but at half the weight? It is defnitely possible, with all the kit coming out these days. That would be something i would love to watch.
It used to weigh 4t fully loaded, now it weighs a lot less somewhere in between 3.2-3.5 when loaded depending on the trip. This is why I'm towing. Project Black on the rear is 53kg as empty. the old box was 200-250kg. The box before that was 300-400kg.
@@Ronny_Dahl Okay thats massive. Well you have a huge challenge on your hands. Changing driving habits or techniques is like a very good bed. Easy to get into, but hard to get out of. I really dont know how you can do that but good luck. Perhaps you may inadvertedly discover a brand new overlanding driving technique. Cheers mate.
I would say that the simple fact that you were ABLE to drive a long distance with a severely damaged rear differential is a testament to the ruggedness and reliability of the Toyota Land Cruiser.
Thanks so much for being honest and caring about your fans. Just a suggestion have you considered a heavier axle to use considering the heavy weight of the load you have and the mods you have ?
This is the content that makes your channel the best Ronny. Honest and trustworthy. No hype. Thanks again from a guy who makes his living from his trusty Landruiser 70.
i have broken 3 short shafts on my 80 in the past 8 years with no damage to the center, was thinking about changing to chromemoly ones but now i think i'll just keep a spare shorty for just in case, seams they are the sacrificial part to keep the rest safe and easier and cheaper to change than the diff itself. thanks Ronny
Sir, that's the correct way to do it. Pack along the right gear oil, hand cleaner, rags, and your favorite bottle of 'assembly lube.' I prefer a shot of good whiskey.
just my thinking, halfshafts are kinda "sacrificial" better they go then a gearbos or transfer case, then one is really buggered
Once I asked my macanic about getting a stronger shafts for my 79 series. He told me it's always good to brake a shaft than braking a diff :)
When your truck keeps breaking short shafts, it’s trying to tell you something. Too much HP is pushing too much weight. Reduce one or both and keep your machine running!
@@rd4660 Correct, or I'd add that the tires may be too large -
I'm not surprised at all Ronny. It's simple physics. Your cruiser carries a lot of weight, the bigger tyres, most of its life it's 4 wheeling in the bush somewhere with the lockers engaged adding more stress to the driveline. Something will give. I've been a mechanic for 20 years and i currently work at Toyota and i understand the GVM upgrades that yourself and others make to these 79's. Unfortunately the vehicle isn't designed to handle the extra weight even with the GVM upgrade, as the upgrade is only on the chassis and suspension and not the driveline. Another thing, the Toyota steel axles twist more as you said because they're softer so it'll take more for them to break. Chrome Moly doesn't flex as much so it's more brittle and will snap quicker under excessive loads. Toyota are smart making their axles the way they do like a "fuse" in the system. Like you said better to break at the outside end than the inside taking the diff centre with it. I'd rather break a Toyota axle and have a spare and be on my way in the bush rather than a Chrome Moly one.
I applaud you for making videos like this to educate people about components and the honesty that goes into it. Fantastic and very rare! That's why you're number 1 mate!! Well done! Love your work! Go the 79.
Makes sense but....Toyota opted to not increase the width of the rear axle for the purpose of saving $ when they dropped the V8 up front. As far as i know all the after market solutions to increase the rear track utilise chrome moly. If only the Toyo factory could produce the VDJ with matching tracks there wouldn't be a need to source these parts. There lies the conundrum
@@cyclemoto8744 there is absolutely no need to increase the rear track width of the 79 series landcruiser unless you do a lot of sand driving. The compromise on capability is negligible on all other surfaces. But everyone's jumping on this like it's a major problem. It's not. If it was, Toyota would have reworked it. My brand new 79 arrives next week and I won't be touching the rear axle. It's a bloody capable vehicle the way it is. If you must correct the rear track, use offset rear wheels. Another thing I don't like about the aftermarket rear axles is the stepped welded plates that form the diff pumpkin. This stepped shape behind the crown wheel greatly affects the splash dynamics of the diff oil being thrown up the rear of the diff housing and over to the front where the pinion is. This shape is critical which is why all diff housings on the planet have a smooth round shape. You'd be surprised the difference it makes to oil flow.
Are you sure this is the case with the Dana axle available for the 70? With regard to the track, in my opinion the drivability is affected when towing, not just with sand driving.
I have personally used a wheel offset ( NOT WHEEL SPACERS) to address the issue somewhat
@@cyclemoto8744 of course I cannot be sure that this is an issue with the Dana axle for the 70 but I'm very sceptical of it as I understand how diffs work. It may reduce service life of the internals if it's not oiling them properly. Was this sufficiently tested by them? I don't know. Have you had bad experiences towing with the stock track width? I think using the offset wheels is the way to go.
I acquired the vehicle when it was in stock form so I have experienced both the standard and increased track. I agree with you that there are many unknowns when choosing to go down the path of an aftermarket diff housing to widen the rear track (off set wheels generally only create premature wear on the bearings). Ronny's video has certainly highlighted the cons: unlike the Toyo short shaft the point of failure on the chrome moly shaft resulted in the diff being damaged. That being said, as stated by others, had the car been towed away instead of driven, the diff may not have incurred any damage. In any case, in this particular situation & location, the expense of the repair (or towing if that had been chosen) resulted in a greater cost when compared to the damage a genuine shaft would have created (in theory of course).
Love your honesty Ronny. Also props to Jason from JMACX for his honesty.
So with the JMAX short half axle breaking and, all the load for everything on the JMAX long half axle it was still strong enough to get you home over 3,000 km? Overall, the vehicle could still be moved under its own power and you got home alive. Given the scenario conditions I'd be going out and buying a Lotto ticket. Thank you very much for the video. Not many would have bothered to give us such a great explanation in plain language. Also thanks to PDP for supporting you (great guys), and JMAX for being honest in a field of manufactures that are not.
No worries mate, agreed I got lucky with being able to drive it home. Could have been expensive towing/trucking from a remote place
@@Ronny_Dahl Can't you take off the shaft and drive with front wheels only?
I’m a mechanical engineer so I have some understanding of this. That helical fracture surface is a classic torsional stress failure. It also failed near/at the spline which is an area of stress concentrations, due to the machining of the splines. This appears to be a classic fatigue failure, whereby a fracture initiated and propagates from a stress concentration and the crack grows and grows and then eventually let’s go simply because there is no meat left in it. This is visually characterised by ‘beach’ marks at the crack followed by a rough or crystalline surface appearance when the shaft finally let’s go in a brittle manner. Bloody hard to diagnose that if you’ve driven it for so long after the failure as most of those tell tale signs get ground away in the subsequent damage. Hope this added something.
based on your knowledge, what would you recommend, weaker Toyota part or stronger after market eqivalent ?
@@rgals2231 Im a metallurgical engineer. The concept of weak and strong metals is only a partial insight into the properties. What really counts in shafts is toughness, and that is the area under the stress-strain curve. Toyota has the metallurgy nailed, rest assured. The others just dont have the resources to optimise the metallurgy. Consider the difference between a copper shaft and a glass shaft. The glass shaft is much stronger in tension or torque, but it has very limited toughness. If there is a stress concentrator in the glass shaft, such as splines, it will fail spectacularly in a brittle manner (with or without fatigue loadings). I have personally broken 3 rear aftermarket diff shafts, on my landcruiser with arb locker. I have since gone back to original toyota parts, and havent had any further issues. But a big part is to find a high level machinist type knowledgeable installer, who uses blueing to line up the crownwheel and backlash, not just slap it together like some mechanics do.
Nothing is unbreakable. Everything has its safe working load.
When you Mod cars, ask for more power, more torque, add more weight, bigger wheels, something is going to fail, if pushed hard enough. That is the price of admission.
Well Done, great video.... I'd have also thought, as metals get "Harder" they also become more brittle.
Hence why we don't have Tungsten Carbide axels....
I wonder if you can make a sacrificial sheer point at the hub end (not in the shaft but on the end plate) that is easily replaceable on the tracks?
Either that or its time for a sheet metal diff to house a 9" with 36 spline, 4340 larger diameter axels.
The amount of torque load that an axle can be subjected to can be estimated by taking the engine torque, multiplying that by the transmission's first gear, and the again by the rear end ratio.
Im not sure how you equate the weight of vehicle into this, but im sure it can be done
Actually, Nissan Pathfinders (at least circa 95 or so) have this on the front hubs. This is kind of 'built in' on the older rigs with 2-piece axles - you'll typically shear the splines or keys before you blow a diff or t-case. I run stock axles on my '48 Willys CJ just for this. It's easier to replace an axle or hub on the trail than to get out with a blown diff.
@@benwinter2420 I posted on this - Look at the mods he's done over the last year. Suspension, tires, engine tune, added weight, but he hasn't changed his driving style. All of his mods increase traction, but he still uses 4x4 and lockers frequently. He _used_ to need them in those scenarios, but not any more. You can't drive a full-time 4x4 system in a 'perfect traction' scenario without a failure. When you bind it up, something has to give. If a tire won't slip, then something expensive _will_ break. The mods add up to make more situations a 'perfect traction' scenario.
Exactly, he went over the specs the rear axle was designed in the first place and it broke; now you have 2 options: upgrade to a heavier duty axle (if you want to keep the rig like it is now and with the same driving style) OR make your rig lighter, smaller tires, easy on the skinny pedal, etc and keep the stock OEM axle.. not much you can do besides that
@@yepitsme431 spot on - make the rig lighter. So the question is how? Ronnie's been working on a lighter rear storage system, so that will help. I also wonder if he could switch to a minimalist (perhaps aluminium?) tray - just enough tray to carry the gear he's got. The new storage system also appears to shift some weight further forward which will help with distributing loads on the drive train, so with the front wheel in the air scenario, this will allow the rear to break traction a little sooner, perhaps saving a shaft.
You gotta admit - Ronnie's got his rig tuned pretty optimally.
considering what you do to bring us these videos and towing a trailer, i am not really surprised you broke a half shaft. it doesn't matter how strong it is the shock loads can be extreme. thanks for all the great content.
Awesome conclusion to the series. Thank you for following up with all the explanations and cudos to the manufacturer for providing all that information.
Learning heaps from your videos, your experiences and your honesty.
Thanks Ronny for your honest and comprehensive explanation. We don't always get this from UA-cam channels.Cheers Darren
Great video, nice of you not blaming anyone but focusing on explaining. That gives you heaps of credibility.
I think having the shaft as a fuse of sorts in the drive line is good. Granted, I know you were away from home base and may not have been equipped to open up the diff. Had you been able to open the diff trackside prior to the 3000km even just to get the crunchy bits out it may have saved the diff center (big maybe). As your experience/research has revealed both axle types are suceptible, in your configuration. Props to Jmacx for being upfront and taking the oppurtunity to share some knowledge. I think overall it would give me more confidence in their product. Thanks to you for sharing your experience with us, sorry for the hit to your wallet.
Well, thanks for educating those of us that haven’t previously considered the related mechanical stresses caused by installing larger tyres, performance upgrades and carrying extra weight.Yes, I will now be more mindful of the more realistic limitations/expectations I have of my own 4x4 after your costly experience. I appreciated the way in which you informed yourself about the different factors involved that can come together and cause such an annoying and trip ending mechanical break down. Many thanks for sharing your experiences and knowledge with us.
I really appreciate the unbiased way you put this video together. I see way to often people jumping to conclusions without all the info. As usual you don't disappoint. Good work!
I used to wheel a Full size Chevy Blazer and it too had a narrower width rear axle and the explanation i received at the time was that it decreased the chance of rollover during high speed maneuvers...safety rating or something of the sort. Also found it very annoying.
In regards to your snapped shaft, having a weak point in the system can be beneficial. just keep spares and the appropriate tools onboard to repair on the trail. Although i too would've thought the 3rd member in this particular case would most likely be the fail point. Toyota certainly didn't make it very easy to investigate the diff, too bad pretty sweet machine otherwise.
Your rig is certainly an awesome build and i look forward to all your content to come! Love every minute of it, It's a great contrast to my world of Canada, Cheers!!!
Good on Jmacx for getting back to you with hard facts, not seen that often from manufacturers these days.
Excellent unbiased review Ronny ......keep up the good work
As always, thank you for sharing your experiences and wisdom Ronny. 🍻
I don’t know much about this stuff, but your presentation was fantastic. I totally get it now, I do many presentations for work, you nailed, great job, love your vids!
Great work, Ronny. No rubbish, no fluff, just plain honest facts. It’s also great to see JMACX standing behind their own product and being so open about the failure rate which really is bugger all.
PS: what happened to the great Ronny shave day????
That’s still coming mate this Sunday on Instagram
Hi Ronny, as usual great and informative, keep up the exceptional job and ill keep paying Patreon, such a pleasure to see inpartial information, and the 79 is a great truck I love mine and look forward to catching up with you sometime in the future
Honest review Ronny. This is what makes your channel. Definitely surprised about jmax but more intregity for a company like that who responded so professionally. Big ups mate
Hi Ronny , looks like I'm not the only one to test to limits. I took out the short side and ashcroft diff on my 4.6 Range Rover HSE going from Ice to rocks in Europe trip. 1900 mile back to home in 2 wheel drive. I unbolted prop shaft from transfer to rear to continue home.
I think you guys just figured out the limits of the equipment.
Considering the mods, the weight of all your stuff and the conditions of the terrain you're going through, it is definitely impressing what these cars can handle!
Adding up the hours of "punishment", it just has to happen one day, as even the strongest parts wear out.
Enjoying Thanksgiving day in Washington State USA watching my favorite UA-cam channel! Cheers Ronny!!!
Thanks for the detailed explanation on why and how the axle shaft failed. Beautiful Toyota truck truck.
Over equip and underload.
Equip heavy and load light.
That shaft would have held if you were just on a paved flat highway, but the incline and sudden pull was what became the proverbial straw that broke the camels back. Safe travels always to you Ronny and your mates.
Good video Ronny. I'm also overloaded for my ram 1500 and rear axel has concerned me and you illustrated for me exactly what and how all this stress can come to breaking point. cheers from canada
Honest bloke or just not sponsored by jmax, either way your a channel I love watching for a raw truthful show. Top stuff to you and your team.
Love your videos Ronny, and your Flinders Ranges 6 Part was awesome. I also took the time to watch your Broken axle video which was very informative and I wish to offer one additional point to consider which is the use of diff lockers, axle wind-up and subsequent potential metal fatigue to related components.
As you know once the diff/diffs are locked they create a solid driveline by removing any slippage through the least path of resistance. So once the diff is locked all torsional energy is transferred directly into the many, many related driveline components.
Wear and tear aside, driveline component failures and fatigue issues generally arise once the torsional stress of a component is "exceeded" and when this happens the component will either break immediately or start single or multiple stress fracture which over time the fractures/stress points will continue to fatigue and over use and time will eventually fail which appears to have happened in the axle splines in your case.
A simple explanation of this this is if you take a pieces of light metal and continually bend it eventually it will weaken and break, this is what also occurs in a drivelines.
In drivelines torsional stresses are dramatically increased when the diff locks are engaged on hard surfaces and are compounded by loads, shock loads and all the other factors you mentioned, i.e. bigger wheels, engine chipping etc. which increase the torsional stresses so the careful and limited use of diff locks as an aid I think is important for component durability and reliability.
I don't have actually have evidence, but I think it's a fair bet that Toyota would have intentionally engineered their axles to 1. fail on the outer and limit consequential damage, 2. limit catastrophic damage elsewhere and 3. make relatively easy to repair.
There are many many factors to consider as serious 4X4 will always push the boundaries and test the limits of people and their equipment, be safe!
Your Diff locker Video ua-cam.com/video/4U1SLSV9wNk/v-deo.html
Once again thank you and keep up the great work, StanM
They should machine a shallow ring groove around the circumference of the axle, near the hub end, a fail point, should the axle be overstressed. Yes, it will weaken the axle slightly however, it may save the diff and make it easier to pull the center section. It would still be MUCH stronger than the factory Toyota axle.
Bang on.
The only reason the diff was damaged was because of the continued driving after the axle failure
and how would you get the broken piece out of the diff centre ??
@@rustyw3858 like they did with a magnet on a pole
It will be broken at the hub, just grab it and pull it out.
Hi Ronny,I think in your case the Dana 60 full floating axle would be the way to go. There is one available for your cruiser. It seems a much stronger assembly compared with the Toyota axle assembly. Stronger splines etc.
Your videos are fun to watch and very filled with information
It would be interesting to see the long side shaft to see any evidence of twisting.
No twisting of damage, we checked it over
Mite need to be xrayed to see micro scoping damage. Have a spare handy.
On the actual video footage of the axle snapping, your face expression = priceless :)
Hi Ronny great video thank you for sharing the only thing I can add is that if at any stage your Lockers are engaged and there is solid ground you put the side shafts under the torque that will weaken or snap the shaft. So I would think this happened in the past, which was the route of your problem.
Thanks Ronny, another great clip, just keep them coming ......
Thank you Ronny for another excellent video. What evidence do we have to prove that JMAX is stronger than Toyota? This is an unique opportunity to send reminders of both axels to a laboratory and get them destructively tested for the maximum torsional load.
An excellent review of the situation, subscribed because of watching this. Hope the refreshed diff holds up now
Very informative and easy to understand your comments and reasoning Ronny so thanks for sharing :-)
That was very informative Ronny. I guess the other big factor in the failure at the time, was the fact you were towing that camper trailer up such a steep track. Sorry it happened to you but it was great you shared the info.
My favorite mechanical fuse is the hub. Warn had a hub kit for Jeep CJ's with notoriously week rear outer splines. They converted to FF and had the same manual hubs on all corners. It probably wouldn't haul much more, but moving hubs around to keep going would be a small chore.
I am glad you quoted the extra load the 35 inch wheels cause on the drive line I have been saying that for years you are lucky to have a car with a low range geared to handle them but are pushing the limits with the mechanical components , great video regards mike
I follow Jmaxc especially since they're a Sunshine Coast, QLD based company. Jason form Jmacx has stated in videos that the chrome molly axles have broken before and the majority was due to extream use/mods. Furthermore, he has developed a 300M 32 spline axel which is even stronger than chrome molly. Was I surprised it broke no because until you pull it apart you just don't know? Also, Ronny, you've got to remember it's a company vehicle which you use what 80-90% off road under all these loads. The more off-road driving you do the more likely things are going to break. If you're going to spend the coin you may as well put the 300M axel in. Jmacx has always been open and honest about their products. Another good honest Aussie company.
Not surprised it happened. While you look after your gear, considering the miles you travel, loads carried etc it was inevitable at some point that something was going to break and will again some day. And it's always going to be the weakest link. The use of diff locks is a tricky topic. If I'm locking in, I always lock front any back and try going as slow as I can at first, increasing momentum after each attempt if required. I even unlock the diffs if I need to try a high speed/momentum drive on an obstacle. My thinking is that the open diff will handle the shock loading a little better and not torture the driveline components quite so much when lifted wheels come down etc. Doesn't always work, sometimes I need to drive hard when locked. Great explanation on the Jmac product. I haven't got one, but still believe it's the only way to correct the track, and the axels are no weaker than the original Toyota equipment. Great work Ronny👍🍺
This is the reason I stayed with stock shafts on my jku. For my peace of mind I carry spare shafts and keep the "fuse" as the axle shafts because that can be changed on the trail and its alot cheaper then a diff.
DANA 60 time Ronnie!! Thanks for sharing it too!
IMHO you’re operating the vehicle beyond its designed capabilities. I know you know this.
Can you lighten your vehicle more? I can’t believe how much stuff you guys take.
All the % stats from Jason should ring some alarm bells.
Good luck with the repair
My vehicle has been lightened and is getting even lighter soon. The stress might have already been done from months before when it was at 4t
Good explanation Ronny in real terms. I could go into some serious details about modulus of elasticity but basically you nailed it stating the axle will have gone beyond it's elastic point previous to the point it blew out. It's unfortunately just one of those things that happen when we run our vehicles heavy constantly & well beyond 'normal' limits, painful to the wallet as that may be. I'm glad you mentioned at the end it wasn't the fault of the components as it's very easy to lose your sh*t & blame the manufacturer when in reality we all push our gear to beyond the maximum.
For a non serious suggestion, fit Nissan axles & you'll be good😜*
*apart from it completely ruining the awesome gear reduction you get on a Cruiser (nothings perfect)
Tings are designed stock for a reason. Manufacturers don't make parts weaker for no reason. It's usually to save something more crucial and expensive. As soon as you go non stock there will be occasional problems when parts are under load, so learn to live with it. Ive got a stock Navara D22 that has taken men everywhere I need to go (some very tough stuff too). All I've added is a snorkel, bash plates, and better shocks. Best forby I've ever had as reliable and tough as nails. Its all about how you drive after all....
Thanks for telling the story mate. Stuff breaks and thats life. Cheers Steve
LOL. Gold!
Many years ago when i used to drag race we would paint a line the full length of the axle so we could track how much twist was in the axle and whether it should be replaced. For Jmax 6 in 1400 axles is not a significant failure rate and from an engineering perspective does not warrant design change, but it would be possible to design a drive flange that failed before the axle. Just like on the 60's and early 80's the smaller drive flange bolts used to shear. Now we have 10mm studs the axle tends to break first
Nice video Ronny interesting to see they broke I wasn't expecting that either. We live and learn though this is why we own 4wds
Same thing happened to my ankle a few months ago. Wasn’t related to an upgrade though, everything was stock.
Fantastic video! There could have been a metallurgical defect within the shaft. The only way to find these defects are using Non Destructive Testing methods during the manufacturing processes like xray or ultrasound.
I recommend that the manufacturer implement these inspection methods during manufacturing. The cost would be insignificant relatively speaking.
You are too good mate.. verry honest- I respect that...
I can add an interesting sequel to this story. One of my customers whose rally car we are currently working on snapped the 13th (or 14th, he couldn't remember) Jmacx axle on his 70 in February 2020. His complete kit had been bought in October 2017. We've been using the same axle supplier as Jmacx for many years and their stuff is excellent. Unfortunately nothing is indestructible Ronny. The best axle builder I ever knew who's since disappeared would never tell me his secret apart from 'its all in the heat treatment'. I could not argue, the national championship winning off road racing car I ran and he built the axles for never had a failure compared to constant failures of some of the biggest names in axles beforehand. BTW, can I assume they sorted you out with a warranty replacement?
thanks ronnie entertaining and informative love the channel and keep up the good work mate,
Just for future reference on the off chance you blow a diff or another axle, it is a very good idea to take out the drive shaft and axels or remaining axels and driving home just on the front diff simply to stop the rear diff from rotating and grinding up chunks of steel with the teeth, both to save your remaining parts from damage eg crown wheel and spider gears, and for safety reasons if a big enough peace of steel gets jammed the diff internals can actually explode and throw the drive shafts off which at highway speeds is usually not good.
I'm more and more happy I stuck with stock Toyota tire size.
Smart man. Same here. Running Pirelli Scorpions and watching Ronnie cry.
Lol might as well drive a soccer mum car, similar capabilities
@@jarrod1687 I live in the vast Mojave Desert in the Southwest. I can offroad every day in my Tacoma. And do. And am satisfied.
great video Ronnie, well done mate
Hi Ronny - there is lots of grades of chrome moly - 4130 and 4140 being most common, these can be heat treated to any hardness, the harder they are the less maluble they are (less twist) so they have different characteristics. The chrome moly shafts should have a thinner section towards the outside so if it breaks you can change it, (I know this makes them weaker but diffs arnt cheap) also dont forget locking up a diff puts huge load on these if its hrad ground, keep up the great videos
I've read lots of trucks have narrow rear axles because this promotes under steer which is generally considered more favorable than over steer as far as driver correction probability. Just slow down to correct under steer. To correct over steer requires a steering correction (it is VERY easy to over correct, especially if you are not experienced with over steer) and most people prefer to be kept pointing straight ahead instead of the rear coming out from behind them. Just about every production vehicle is designed to under steer first at the limit. Most drivers almost never experience a lack of traction at the limit and panic is the first thing that happens so under steer is generally considered safer.
I believe how this works is the wider axle has more weight transfer and this results in reaching the traction limit sooner on the axle with more weight transfer. The wider axle is a longer lever and more force from the roll of the vehicle is resisted by the wider axle. The extra force resisted is transferred to the outside tire and vehicles are designed so the front wants to skid first resulting in under steer.
Concerning chromoly shafts, I've always wondered if a fully hardened shaft is what you want. Like Ronny says, you get less twist and hardened steel is more brittle. I guess it's a balancing act between ultimate strength and the axle's ability to handle shock loads. It's very convenient the stock yota shafts break at the flange. No metal bits in the center section and I suspect it's easier to change a shaft which has broken at the flange. To remove Ronny's shaft the entire center section had to come out. I'm sure the yota engineers intended for their shafts to break like that. Good engineers consider serviceability. Of course that is one of the compromises with chromoly shafts for the added ultimate strength. It all depends on your application.
I have a landrover discovery 1. 265 75r16 mudterrains. ARB air locker at back. I have broken 4 short shafys and 2 long shafts every time when i use difflock. These are all landrover shafts. You do get Ascroft chrome molly shafts which apperently does not break but you pay 6 times more for these axles. I want to try it when i have money. I am also frustrated. Nice video
Great and honest video. I’m not in the market for an upgraded rear end but anyone that is would gain a useful insight.
You make the ideal guinea pig since you spend so much time off-road, pushing your gear.
Tough luck with the breakage and good on you for representing jmacx in the way you did. It would be all too easy to pay out, on the compa. In light of common sense, engineering based explanations you can inform us while making a more informed decision for yourself.
👍
I agree with a few statements above. I wouldn't have spent the cash on a new aftermarket axle and just went for a Dana 60. Match gears for the front and slap in a e-locker to replace your current one. No more problems. Just my thoughts. Love the channel.
not bad thoughts either mate, problem is money I don't have one of those trees with notes growing on it :D
There’s an interesting video on UA-cam on the manufacture of F1 prop shafts out of carbon fibre. You should see the results of steel vs carbon fibre when used in a torque test machine - it’s phenomenally strong but phenomenally expensive! Be perfect for this job but as you quite rightly say - it’s only ever as strong as the components it fits onto!
Great balanced video Ronnie. From the UK 👍🏻
Maybe check the shafts after each outing to see if their twisting/cracking? could always score a ring around the shaft on the wheel side so if it does break again it will break where you scored it, saving $$$ for another diff. I think only other option might be custom axles like a dynatrac prorock 80, but you'd have to change to 8lugs.....among other things lol
I think Ronny knows he requires 2 difficult upgrades.
1.Reduce weight. These guys carry too much crap. Too many spares. Too much water. Too many conveniences. Yea, I know, I know. I know.
2. Adjust driving style. You can’t go hard and fast ALL the time. Ask your wife …
Part 2 of No2: haha
@@cyclemoto8744 hahaha
Thanks dad....
Of cause you got that right, BUT you know as well as i do, the after market Industrie likes to make some money
yeah leave your water at home, it weighs too much
You are the first and only person i know that broke a landcruiser diff... really these things are really really really hard to break... and u did it... who on earth u got it right i dont know but yeah 🤣
(Edit)... and how do u snap a chromaly full floating shaft?.. ronny i am really surprised... u are brutal😅😅😅
All in one word. Weight
@@MrJarmore yeah... buts its a full floating shaft... i can understand if a few teeth break off the ring and pinion but twisting and snaping a full floating chromaly shaft
I think he was locked front and rear... and pulling a trailer. His rig has limited down travel so he frequently gets a tire in the air... forcing the opposite shaft to take the full load.
EDIT: i guess he was only locked on front. But lifting tires, spinning then setting them down will snap stuff.
@@lumpskie yeah that's it mate. I have a very heavy 60, driving an off cambered wheel lift section. So essentially all the load was on the driver rear axle. It went bang just idling up.
Go hard or go home lol that's how I ended up with familiar problem with my JK but only thing was broken was spider gear then it worn out the crown and pinion too..
Great video. Power, tyres and weight. You have upset the magic ‘factory’ formula of reliability and strength in a Landcruiser. The engineers in Japan will be sad and disappointed that you exceeded the limits they set for us when the VDJ came out. You will now be in the ‘perpetual circle’ of pain of modification.
Thanks again for the detail and research.
Keep them coming.
👍
Ah, but did he now? The stock toyota diff took the pain, but the aftermarket shaft bit the dust 😉 So toyota engineers can still sleep well tonight 😊
I have broken a Toyota one too
@@Ronny_Dahl Sry, was meant more as a joke, and kudos to the diff (I daily drive a 110 Lux so may be slightly toyota-biased) Thank you so much for all the awesome content, truly one of a kind, I love seeing how much you guys enjoy each others company :) Frosty greetings from Finland!
@@Ronny_Dahl detune the engine to factory specs and smaller tyres?
It might be a case of designing an inspection routine set by distance traveled and severity of 4WD driving or time
Especially with how easy toyota axles are to slide out. Dont even need to take the wheel off
Haha nice little teaser of the new tray setup ronnie!
I really like the full floating rear setup
interesting how the cracking is from the sharp part of the splines groove. A classic place for a stress riser. maybe if the edges were champfered the cracks wouldnt have occured?
However the twisting was still there. I like the comments for a designed in failure point
around 700 half shafts made say 15 broken i doubt every broken axle gets reported even if it was 20 that still a good ratio and the honesty from JMACX is grate its something lots of other big company's are missing these day.
I have not taken any axles apart for twenty years now but when I did I noticed that many manufacturers had ground the outboard end down a bit jus short of where the hub splines were, so that there was a deliberate breaking point. That way the dif will not get written off by shrapnel from exploding half shafts.
I'm sorry but I laughed a bunch of times at this video.
Very informative.
Love your channel.
Thanks for all your hard work Travis
Ronny Dahl At 15:44 I noticed the front passenger wheel jumped up a bit as the rear shaft broke. All 3 other wheels seemed to have grip as the front drivers wheel jumped up. Wow massive transference of energy as the wheel came down thru the entire drivetrain.
I always prefer factory original parts. Thanks for sharing. Godspeed & Happy Trails :|
As a forestry winch operator i would never advise towing wood unless you have the front of the log raised off the ground or on a sled or logging arch, incredible forces come into play when a log digs in, we have had cables snap, winch drums twist, logs flip and smashed bearing casings all from logs digging in the ground or getting caught on stumps and roots. we use a high lead system so our snatch blocks are always as high as we can place them, it can be equal to putting a strop round a healthy growing tree and driving off, somethings gonna break.
Here is the U.S. guys run Dana 60 front and Dana 80 rear axles on jeeps all the time. The 60 and 80 are off much larger full size trucks like F250 and F350s . Or guys will even run 1ton axles . Is this an option in Australia? I know you guys have strict laws when it comes to vehicle mods . Anyways Ronnie another cool video
Dana 60 and 80’s are an option in Australia
Can you run a 60 up front and a 80 out back with the corrected withs ? I’m sure they are super expensive for your rig. You can easily spend $10,000-$20,000 for a fully built set of axle .
The same axles are available for Jeeps in Aus.
There is a bolt in kit for a Dana 60 for the rear of the 70 series which also corrects track.
More than that is usually not needed since it can be hard to legally run big tyres.
A modified 80 series axle should be more than enough for most people, and Nissan Patrol axles are strong too which is why most comp trucks use them.
@@Ronny_Dahl Is the Dana60 or 80 stronger than the stock 70 rear axle?
The 60 is stronger than the stock 80 series axle, which I believe is the same as the 70...
Hello Ronny I am not surprised you snapped a high tensile shaft high yield point softer steel that's why you shouldn't retension hitensile bolts the second time they fail without warning. One other thing i would consider did you damage the diff when you snapped the toyota axle and i seem to recall you fixed it in the bush. Great video as usual frank and informative.
Great stuff as usual. The best!
Excellent vid.
Thanks for the video
Yep, if you keep increasing the load something will give and normally the weakest point. So what is the cost analysis between Jmax upgrade + new half shaft + new diff versus no upgrade a new Toyota half shaft and maybe carry a spare Toyota half shaft knowing it's a weak point. Excellent video and honesty is always appreciated! 👍
Interesting stuff. Oddly enough my missus reckons that your trucks diff and me share the same common problem...short shaft weakness. Sucks about the diff mate, keep up the great vids.
PDP must be very busy lol, always fixing and working on your 4WD. :)
Great stuff mate. Keep up the awesome work.
I don't know that there would have been an 'exact moment'. Think of these things:
First, it's a full-time four wheel drive system - the type of system that shouldn't be used in a 'high-traction' situation. For a 'normal', unmodified vehicle, this typically means 'dry pavement'.
This isn't for Ronnie, it's a general explanation of what's going on in a high-traction 4x4 scenario.
When you drive this type of vehicle with four wheel drive engaged in a high-traction situation, it will 'load-up' or 'bind' the entire driveline. This binding is what makes it hard to take a four wheel drive vehicle out of four wheel drive. When this happens the following is _all_ happening:
1- Axle shafts (or half-shafts if you prefer) are starting to twist (I should say 'under heavy twisting loads', but I'll use 'twist' for brevity)
2- Drive shafts (or prop shafts) are starting to twist
3- shaft joints (U-joints and CVs) are being torque loaded
4- The pinion gear is starting to be forced away from the ring gear (or crown wheel) in the differentials
5- gear shafts in gear boxes are undergoing stresses that force them both apart from each other, and to try to to twist in a plane usually aligned with the ground depending on the design on of the gearbox. (These are the stresses that can cause a transmission or transfer case to crack or split open.)
6- engine and transmission mounts are being loaded in the opposite direction of torque
In a 'perfect traction' situation where none of the tires can slip, one of the above components will fail. As noted by Jmacx, this failure can have a knock-on effect and damage other components.
Now lets look at traction in this case:
The truck has front and rear locking differentials to improve traction in less-than-ideal circumstances, such as mud, sand, gravel, etc.
The truck is equipped with tires and suspension designed to maximize traction.
Tires are commonly aired down to increase traction.
The vehicle's high weight also increases traction.
The truck has been tuned to produce more torque.
Together, these modifications _increase_ the number of 'perfect traction' scenarios. This can actually increase the chances of breaking something. The operator needs to understand this and carefully choose how to set the vehicle up for a given obstacle. Something _has_ to give. If a wheel can't slip, something expensive _will_ break. Maybe not immediately, but it _will_ break.
Last note: when one part fails under stress that other components may have been damaged as well. You should inspect all u-joints, axle shafts, mounts, and cases for other damage. Then pack along spare short-side shafts.
Keep up the awesome trips and keep 'er shiny-side up!
Les
This post has been edited to remove the poster's inane remarks and uninformed commentary. My apologies Ronnie.
So true. This should be talked about in a video
It is possible to make stronger axles in the same form factor. The problem is that it's simply not cost effective due to material costs etc. While chrome moly is strong there is a spectrum that starts expensive and ends in mortgage territory. en.m.wikipedia.org/wiki/41xx_steel
I don't know the specifics about the jmax stuff just suggesting that there's almost always a stronger metal.. only costs or patents keep them from mere mortals.
Correct first post ive seen about this. 4130 is stronger, about twice that of factory 750mpa. I run maxi drive hy tough axles they rated at about 1100mpa which is 3 times the tensile of stock and also slightly less brittle than 4130. the best is 300m about 1600mpa this is used in high end axles and input shafts in gearboxes of high horsepower drag cars etc. Other factors in failure can be attributed to the machining of parts leading to stress risers and heat treating of materials
@@SomervilleMetalWorks heat treatment is hard to get right. If it's not equal the metals won't be equally tough throughout.
Great video mate. I learn a lot from your vids
I hope you learnt not to screw with Toyota engineering. Toyota did everything for a solid reason. Ronnie is a massive fail as an engineer. If it was not for Toyota's engineers he would have been sitting on his behind in the bush.
a bit sad having a breakage Ronnie, but as a great man said "if you go looking for the limit, don't be surprised when you find it" maybe if you had a std clutch or an auto transmission there would be less shock load on the axles? don't machine a groove in the axle at the hub end as has been suggested below, I would taper the shaft down slightly towards the hub and polish it to eliminate stress raising ridges. BTW 4140 or 4340 are great shaft making steels in annealed condition they are not so brittle.
Thats bad luck Ronnie, but thank you for investigating fully and giving us a clear explaination. Surprised the manufacturer doesn't in-build a safe fail point into the shaft. I would have thought the OEM Toyota one does. So as a long term solution will you be carrying on the 70's weight loss diet a go down to 33"'s?
This is exaclty why i run stock. I did an fjcruiser super mods. Things broke, Toyota said “void warranty”... since then i put up with weird track, lower ground clearance etc... guess what? No drama! 😀
I've got RCV front axels in my jeep. I'll be doing some research to see how many of those have broken.
I have always had other 4x4 ers give me stick as my choice of 4x4 is a Landrover Defender and this make have always had a reputation of breaking axles, although I have never had this experience myself. Rightly or wrongly I believe the axle design is a deliberate weak point to reduce the possibility of additional damage to diff centres as you have shown. Axles in most cases are easier to replace or remove entirely on the track without further diff damage through rotating parts interacting with metal debris if the drive shaft is also removed. The Landrover design differs from Toyota and many others in that they are a fully floating axles front and rear meaning splines on both axle ends. This makes driving in front wheel drive to get you home in a case such as this simpler to achieve as no rotation will occur if the tail shaft is removed before any further travel.
Think I’d be going down to 33’s. That 25% extra stress for a limited advantage isn’t worth it! A lesson for us all; as another commenter said, better a weaker shaft that will shear before other parts of the drivetrain!
The Toyota OEM shaft is designed to shear at the hub... TO PROTECT THE DIFF!... screw with that and you are buying new diffs every time... some rich people!
Hi Ronny, i have an idea for you. As it stands, you upgrade almost everything on your vehicle all except the engineering in crucial parts. So as a result (short from upgrading to lorrie gearbox and axials) you wil always have this nagging feeling at the back of your mind that your axials might snap when you do the ruff stuff. How about taking off all the extra weight and make it a project to see if you can still get all your extras but at half the weight? It is defnitely possible, with all the kit coming out these days. That would be something i would love to watch.
It used to weigh 4t fully loaded, now it weighs a lot less somewhere in between 3.2-3.5 when loaded depending on the trip. This is why I'm towing. Project Black on the rear is 53kg as empty. the old box was 200-250kg. The box before that was 300-400kg.
@@Ronny_Dahl Okay thats massive. Well you have a huge challenge on your hands. Changing driving habits or techniques is like a very good bed. Easy to get into, but hard to get out of. I really dont know how you can do that but good luck. Perhaps you may inadvertedly discover a brand new overlanding driving technique. Cheers mate.
I would say that the simple fact that you were ABLE to drive a long distance with a severely damaged rear differential is a testament to the ruggedness and reliability of the Toyota Land Cruiser.
They said : currently 0.5% fail ratio, but it's until now....
I hope you'll be lucky for your next one.
Great video
Thanks so much for being honest and caring about your fans. Just a suggestion have you considered a heavier axle to use considering the heavy weight of the load you have and the mods you have ?