E46 M3 Differential Input Shaft Seal Guide + M-Clunk Diagnosis, Refitting the Diff & Test Drive
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- Опубліковано 6 лют 2025
- E46 M3 Differential Input Shaft Seal Guide + M-Clunk Diagnosis, Refitting the Diff & Test Drive
Following on from the previous video where I removed my BMW E46 M3 differential and brought you up to speed on the car and its multiple diff problems, this time I compare two diffs on the bench, swap the input seal, refit, and find out if the “known good” second diff I picked up was a scam or not.
Here's what I used in this video:
Uprated Input Shaft Seal: ebay.us/WnQ1I3
BMW Revised Diff Bolts: ebay.us/c2tVLr
Castrol Transmax Limited Slip 75W140 Oil: ebay.us/Vqaciq
Original BMW SAF-XJ 0.5L + FM Booster 83222282583: ebay.us/rzk23W
Jenolite Wax Oil Spray: ebay.us/fDAS70
E-Torx Spanners: ebay.us/LAkQFk
E-Torx Sockets: ebay.us/YPEsBZ
Dewalt 18v 3/8 Ratchet: ebay.us/Wk14qg
With my original E46 M3 diff on the bench beside a spare one I picked up described as "known good" I was finally able to compare them and determine if there are any obvious issues with the original or at least points of difference in terms of play.
Surprisingly the new diff I picked up seemed to be clanking more when I span the input flange by hand, but I was correct in suspecting this was more to do with the fact it was drained of oil than anything.
The most prolific cause of E46 M-Clunk is said to be the right-hand output flange of these M3 differentials. Due to the design of the internals, the right-side flange has a shorter spline into the diff, and develops play over time, leading to clunks.
The new differential I had seems to have significantly less play versus the original one, which was encouraging to me. Further to that, my original diff seems to behave strangely to inputs, if you let the diff settle for a moment, it's very stiff to start it turning, almost feels like it seizes up slightly. When its turning however, it turns freely, it's just getting it to start.
With that strange development, I concluded fitting the new differential was the best move, so this is the unit I opted to fit my new input shaft seal to.
The new input shaft seal I picked up is an uprated part which is supposedly improved from BMWs original seal, it uses a cup design rather than a grooved design to prevent the diff oil from escaping. I believe its the grooves on BMW's design which wear down over time and permit the leaking of oil.
The video serves as a good guide for replacing the pinion seal on your M3 diff. First remove the input flange by careful removing the nut which holds it in place. Count the threads as I did, as its absolutely essential that this nut is put back in exactly the same position as it was originally. It doesn't just hold on the input flange, it also sets the thrust of the pinion on the crown wheel. Setting it incorrectly will terminate your differential prematurely, and it will probably make a horrific noise while in demise.
with the input flange nut, and the flange itself removed, extract the original diff seal and get your new one carefully pressed in. Button it back up and your job should be done, no more diff leaks.
After doing this successfully, fitted the diff to the car using new rear bolts, the revised E-torx ones with the shoulder supplied by BMW. It was quite tough but with help from he old man and a bit of bickering, we managed to get the diff in place, the torque settings are shared in the video too.
I'd fitted the spare diff with the original diff's oil, the stuff supplied by BMW I'd put in only a few thousand miles previous, and topped up with some Castrol limited slip oil to meet capacity.
Following a 50 mile test drive, which included some tight circles to circulate the diff oil into the clutch packs and reduce the groaning noise, and some spirited driving, I concluded that my M-Clunk is considerably improved. Although still present, it's considerably reduced.
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Yes mate its not bad at all but theres always something that needs doing but thats all part of the fun of these projects 😁 yes be worth doing but since ive done mine i dont like taking it out in the rain 🙈🤪 looking forward to more m3 contents on your channel 👍
Haha indeed, its a BMW after all! They do like to ask for attention. 😆 I also try to avoid rain so I can avoid letting it deteriorate, but I especially avoid using it in winter on salted roads now. Absolutely no way, even though I used it all year round earlier in my ownership.
I've started treating the undersides of my cars with a lanolin product called Buzzweld Chassis Guard. Check out my E30 video about that. Quite impressed with the protection it gives, and its very easy to use and not dear. I am going to treat the M3 with it too because I might as well, will feel less bad when getting caught in the rain.
Not alot of people know why it clunks.
The reason why is because of the actual front mounting diff bolt loosening because of vibration, which causes the Diff to kick upwards into the chassis and it creates a thud
the shaft of the bolt hits the internal sleeve of the bushing.
The only fix that i found was to fit a hardened bolt with a nord lock washer so it doesn't loosen during shifts.
That is definitely a common one, I've heard of the front bolt working its way out entirely and ending up sat on the undertray. As you can imagine, that leads to an absolute clunk-fest. 😆
However, that's just one thing tat can cause M-clunk, and it didn't apply for me. My front bolt was in solid as the day it was fitted, took use of a breaker bar to get the thing moving, yet my original diff clunked like heck.
Awesome stuff. Seeing this has given me the confidence to do my own. Not like other videos that say you need 3 special tools and a hoist.
Awesome, really glad to give you confidence to work on your own M3. It's not rocket science with these luckily, even though they are a pain to work on versus older BMW models. Just requires a bit more patience.
Get the car lifted enough to work under it, in a secure and safe way, and you can't go far wrong with mostly basic hand tools.
A little tip for the axle grease, a roll of disposable cake decoration icing bags is a nice clean way of dispensing and storing, a small cable tie on the big open end to seal once filled, and snip off the pointy end to any size for the job and squeeze. I found to be very good for re-greasing deep into CV joints in particular.
Output shaft torx bolts £15? ebay, Amazon yes OK? Although, BMW £7.16 each.
In fact I am finding ebay and Amazon to be far more expensive for certain parts than BMW main-dealer, what's that about?
Do like your videos.
Excellent piece of advice there, I would have never thought of that. I don't do much baking... 🤭 I suspect I will get to try that out at some point so thanks.
Dang, I am noticing this occasionally as well. Maybe crafty people are buying from the dealer and reselling on convenient platforms for a profit.
I should be careful to check that going forward rather than assuming. Glad you enjoy the vids. 😃
Ah right will look into getting some i think or certainly somepoint next year dont fancy doing it at the minute 🙈😁
Fair play, never fun crawling around on the floor in winter 😄
Yes mine was my daily but now hardly used 🙈😁 oh really i dont think ive heard of that stuff might be something i concider iff price is decent so you done a review onnit with your e30 i might have to check that out as its getting that balance for something that lasts but isnt tacky enough to attract dirt n dust
Exactly, really impressed with it so far remarkable stuff. The Buzzweld stuff I used is much better value than the Lanoguard stuff and I think its relatively similar.
Good work with your nice M3, and nice to see your videos here 🙂
Cheers pal! 😃
Im a new subscriber great 2 videos ive watched on your amazing m3 i have a phoenix yellow one thats had a nut n bolt resto underneath and many other things are we going to see more e46 m3 videos
Hi Mike, sounds like a great M3 you've got there. My Imola is still a long termer, I've had it for a long time and I can't see myself rushing to part with it any time soon.
Hopefully one day I can pluck up the courage to dismantle it and restore it properly like yours has been, but right now it's in good but usable condition.
Ultimately all cars are projects, so definitely more to come on my M3, welcome aboard! 😄
Would you like to make a video on the performance upgrade? We would support it with parts.
I'll bet he doesn't want to take the diff out again for a while 😀 Love your instructional videos on rebuilding BMW diffs by the way
Long term I am planning to rebuild that original diff and refit it fresh, in the hope to solve the clunk entirely. So depending on the details, I could be very interested in working with you on that. 😁 If you reach out to me via email I'd be happy to discuss further. spannerrashteam@gmail.com
@@rotateonthis Haha! I suspect by autumn time I'll have forgotten how much graft was involved. 😆
@SPANNERRASH my guys from customer support will be reaching you out soon. Personally, I liked your video very much. I would love to see you install and review our parts.👍🏻 Especially we are specialised for M-clunk problems from E46 to F80.
@@RacingDiffs Thank you for the kind words! 😃 It sounds very promising that you'd be the right guys to partner with in this case. I look forward to hearing from your team. 👍
Do you have a link for the seal you used as the link in description doesn't work
Hi Jason, strange, they must have made a new listing for it, here it is: ebay.us/WnQ1I3
@SPANNERRASH thanks for that much appreciated
Classic!
Cheers 😃
Especially on a damp floor in garage that leaks 🙈🤣
Tell me about it 😂
Might have to look into it its trying to find something that dont attract muck and grime aswell
if you don't put it on too thick and give it time to dry, it won't end up too tacky. I think its a decent tradeoff for the rust protection personally.
serious harry potter vibes with that nine and three quarters
Haha yeah that also occurred to me afterwards. It's quite spooky! 😆
The realm of reasonable clunk...haha love it
Haha! That's where I'm trying to stay 😆
@@SPANNERRASH we all are! Another great video.Love the amount of work you put in and explanations are top notch. Superb channel.
I’m new to BMW’s and picked up my first one (E46 M3) a couple of months and the clunk started last week…
I’m trying to figure what the “realm of reasonable clunk” is because I want to keep driving the car until I fix it, but I don’t want to do more damage to it. All of my bushings look great, and there isn’t any play in the diff. It’s just clunking around lol. Mostly in first gear/low speed. Under power I don’t notice it at all.
Any update about what is causing that Clunk and Hopping ?
Certainly play in the output shaft, swapping in a less worn diff has made a huge difference for me. I can recommend that or a rebuild if you want rid of it once and for all.
@SPANNERRASH thanks for the answer sir, but i won't know the cause of the problem to realize the worth of fixing it or to go with a swap. Don't want to buy another one with no reason ✌️
Looking at putting the diff back, i'm totally not looking forward putting mine back in 😂
Haha Good news is it's probably not worse than taking it out! E46s just aren't fun to work on compared to E30s it seems. 😆
☔️☔️☔️💧💧🙈🙈🤣🤣