If only all videos were this clear, concise, and well done. The old saying is "A picture's worth a thousand words" and this animation is worth a lot more than that. Fantastic job DLMaster!
Actually its a faulty diagram. Read my comment above of why this is. Faulty diagram. The pinion itself and the conical bearings, on each end of the pinion, have to have zero clearance or the pinion would tilt up or down randomly during use. Therefore all in and out play at the drive shaft flange must be zero clearance to cause each cone inner bearing to ride straight on the races. So that is an absolute that must be addressed and the location of pinion teeth with the ring gear would have to be done with a pinion that extended farther in its length by the machining maker or a ring gear that had teeth that extended farther inward. But you cannot have in and out play at the flange at the nut
Hands down, the BEST video on YT explaining the principles of diff adjustments. In 7 minutes and 16 seconds this man achieved what others couldn't achieve in hours of screen time!!!
I changed the depth adjustment which changed the backlash. I reset the backlash to .010" and retested the contact patch which moved slightly. What don't you get? I'm willing to explain it.
I overhauled a lot of differentials in the past; and your video hits the mark. Most people don't understand how precise the set-up has to be; and how a very very small miscalculation can cause all types of drivability issues.
Should emphasize the fact that contact patch and backlash should be checked with the axles in the differential (loaded) and tires on to offer some resistance in drive and coast.
Thank you for your comment and observation. The axles do not have to be in and in this removable design that is really difficult. It is very important to provide a load or resistance to rotation to obtain a good contact patch pattern. What you can't see so well is I built in a braking mechanism that is applying rotational resistance to the ring gear. This is adding enough load to provide a good pattern. The objective of this video was not to show how to perform a contact patch pattern but instead to explain how the pattern is effected by the change in drive pinion depth.
This really applies to all differential designs however the 9" style was much easier to make an adjustable pinion to demonstrate the effects pinion depth has on a contact patch.
Iv never rebuilt a rear differential before but I’m going to have to rebuild the rear differential in my 96 Ranger Splash. This video helps me a lot and gives me the confidence that I can do it! Thank you!
Good information. I've had production experience setting up construction equipment spiral bevel gears, same system applies. A little toe bearing centered up is acceptable as opposed to heel bearing. The toe of the ring tooth being thinner will flex and spread increaseing the load bearing pad back towards the heel.
Pretty clear and educative. I have learnt 2 ways of differential gear adjustment from you, i.e using dial gauge measurement and contact marker visual inspection. Thanks!!
The Dial indicator is measuring Ring to Pinion gear backlash (clearance) The gear contact paste, is indicating Pinion gear engagement depth with the ring gear. Two very different measurements... What you are not told is in order to setup a pinion on an 8.8 Ford, it requires the purchase of an extra (setup) bearing, identical in manufacturer to the bearing you will finally use. This bearing must be modified to "slip fit" on to the pinion so pinion depth can be setup. Additionally, you will need a few extra crush sleeves for this process...
Thanks. I'm glad you enjoyed it and found value. Your comment mirrored 99.99% of the comments for this video. My videos are all from and educational perspective with an emphasis on quality video and audio with the smallest length possible and to be concise, complete, and accurate as possible.
Excellent video explaining Ring and Pinion gear relationship. The most helpful to me was the use of gear contact paste on just two teeth. I see other videos where its slopped all over the entire ring gear. Your approach makes better sense.
My factory training taught me to paste every tooth and it can revel some information about the setup however in real life I paste 4 teeth every 90 degrees. This gives me a feel for the setup.
Thanks. I do NDT in a shop that repairs speed reducers but don’t know much about their operation. So this is what the assemblers are doing when they have a gear set together but keep tinkering with it.
This video is great and helps a lot. The only thing I don't understand is when you say you have to move the pinion gear father away from centerline, I don't know which way you're moving it because I can't see it moving in the video.
Watch from timestamp 0:26 to 0:31 and 1:16 and 1:22. The pinion moves to the left but I don't like to say to the left because what would happen if the image was flipped 180 degrees or even just 90 degrees. So it's not a good idea so say the pinion moves left, right, up or down but instead talk about in relationship to the centerline of the ring gear.
I tried your suggestion with that "straddle mount" during a third date. It didn't go well. And I assure you my pinion shaft was large enough even though my date didn't think so. Just saying. But thank you for the video. It was worth a try. You RoCk!
I'd like to see you continue moving the pinion away from the ring or "increasing the pinion depth" until the pattern went unacceptable the other way. I just set up my Toyota 8" and the drive pattern you found acceptable I had at one point, but when I read the pinion teeth it was showing a shallow mesh leaning towards the diff centerline or toe (this is a rockcrawler) - so I pulled another .010" from the pinion head stack and ended up with a nicely centered oval drive & centered comet tail pinion pattern - but my coast pattern still looks similar to your drive pattern and I'm not sure why.
Your drive side pattern is your most important and the biggest goal is to make sure the pattern is not running off the toe, heel, face or too deep into the flank. It would be great if drive and cost would always both be perfectly centered but that is rare. In fact I prefer the drive side to be slightly towards the toe and coast to be slightly towards the heel. I do this because under heavy load the pinion will thrust slightly towards the front of the vehicle causing the drive and coast side patterns to center. If you are working on a front diff and it's flipped so the pinion centerline is above the axle like front diff's on 4x4's offend are for ground clearance the drive and coast sides of the ring gear are reversed. The drive side is concave and the cost side is convex. I hope this helps.
Very clear video in showing relative positioning and optimal settings checks. Could this test determine if a used pinion gear/ring gear combination , has been worn beyond suitability for reinstallation practicality ?
severely worn ring and pinion sets are normally noticeable by visual inspection however they will often exhibit patterns that look like thin lines as compared to oval or triangular shaped.
Thanks so much for the video! It really made it clear for me. I was wondering if a used rear axle was making noise from say too much back lash, could it be made quiet again by making the right adjustments to the back lash/wear pattern? Or would you have to rebuild the rear end and get a new gear set? The rear axle has 120,000 miles on it and the teeth on the gear do not "look" bad.
If you are getting clucking from too much backlash especially when switching from D - R or R to D you most certainly can change the backlash adjusters (Shims or Threaded Adjusters) to correct or reset the backlash. You won't need to mess with pinion depth and you should not have to worry about contact patch. As long as you have the dial indicator and the tools and methods to make the adjustment. Just make sure to check your backlash in at least 6 to 8 different locations around the ring gear and make sure the backlash is never smaller than the minimum specification. If your getting humming or moaning noises that is not a backlash noise and readjusting the Backlash will not fix this type of noise.
@@DrivelineMaster the noise I am getting is a moaning noise from about 30 mph on up. It moans when I am on the gas. If I let off the gas and coast it gets a lot quieter. I changed both rear axle bearings as on side was bad. I didn't see any play in the pinion bearing and it spun freely. There were no visual defects in either gear. What do you think is the cause? Thanks in advance
This is a description of a classic rear drive pinion bearing noise. Sometimes worn gears will do this but it's not as common as a pinion bearing. Normally if it's gear noise you can't see the wear but a contact patch can sometime identify worn gears. The contact patch should be non symmetrical triangular or oval. Normally if the gears a bad the contact patch will be a straight thin line. Place a listening device such as a mechanics stethoscope or you can use a screw driver or extension bar up to your ear while holding the other end against the differential housing in different locations. Once near the rear pinion bearing and once near the front pinion bearing. Do this with the wheels off the ground and someone driving the vehicle accelerating and decelerating as you listen. I put 95% chance your problem is the rear pinion bearing even if rotation feels smooth when turning it by hand.
Are these gears face hobbed or face milled? Also does that actually even matter when checking patterns? I've been trying to learn all I can when it comes to setting rears up, love this demonstration!!
I believe this is a face milled Five-cut gear set. If you have been doing some research then you most likely found this URL. gearsolutions.com/features/face-off-face-hobbing-vs-face-milling/ also this from Yukon gear www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwif_e-JxbL0AhXloFsKHYN6DQ0QFnoECAIQAQ&url=https%3A%2F%2Fwww.yukongear.com%2Fweb_images%2Fpages%2FBrochures%2F2-Step-vs-5-Step-Gears.pdf&usg=AOvVaw2q8lfMkwNzdKq7Hzfd8FJ-. The pattern is different and moves across the tooth differently depending on how it's cut.
So what were you adjusting everytime you had to move the backlash back to 10 thousands ? How do you read the number on the pinion gear to determine what shim pack is best and closest to start with? If it's a minus number foes that mean you need to add shims to bring it forward to the ring gear or have less shims to move it down to that measurement from the centreline?
Nice vid explains a lot I have a better understanding of contact patch but what happens if one side is ok but the over drive side (back side is off ) how would the adjustment be made ?
The drive side of the ring gear tooth is always the pattern of most concern. If the coast side is off a bit I don't worry too much as long as the drive side is where I want it. Two other factors effect contact patch. Backlash and worn gears. Although Backlash effects the pattern differently (hey, that give me an idea on a new video) worn gears will create all kinds of weird patterns that won't make any sense.
The dial indicator is a standard 1" dial indicator. For in the shop I normally use one that can be setup using vise grip locking pliers similar to this Central tool. store.dealershopusa.com/product_info.php?products_id=77440&gclid=EAIaIQobChMI1sHB_4Gd_gIVkR-tBh0ZUwCtEAQYBiABEgJLgPD_BwE The spanner nut wrench is a Mazda specialty tool that is adjustable making it universal but I don't think it can be purchased anywhere except from a Mazda specialty tool store. To perform the contact patch watch this video. ua-cam.com/video/UIIk305-zlQ/v-deo.html. To adjust backlash watch this video. ua-cam.com/video/d9cxw9d-css/v-deo.html. If you would like to Mazda spanner nut tool number write back and I will look at the tool one day next week and write you back.
@DrivelineMaster I would like to get into differential rebuild. Most people remove the pinion and check. I notice he didn't do that. He was using a tool to adjust the depth and lash. I'm interested in that tool also. Was that the Mazda tool you mentioned? Thanks
The Mazda tool was the spanner wrench that I used to adjust the backlash. I did not use a tool to change the depth. Instead I customized that differential to allow me to change the depth just by turning a threaded rod. For all other applications pinion depth is adjusted by disassembling the differential and changing a shim thickness. I also have a video on how to use a pinion depth measurement tool. You might want to look at these two video's. ua-cam.com/video/gk6imita0cc/v-deo.html and ua-cam.com/video/QL-dmhfSj6k/v-deo.html and these two as well. ua-cam.com/video/_bUh9NEMldI/v-deo.html and ua-cam.com/video/bxi7EiQzo9E/v-deo.html
Subscribed; You are the Master, great explanation; just out of curiosity what would it take to get a perfect pattern on both sides,and is it possible? and any advantage to doing that,just for (heavy,towing etc ) street use?
It does happen but not as often is I would like. Start with a case with zero axial run out. Add a quality gear set with tight tolerances. Have it assembled by someone who takes a lot of care and attention to details. Finally the proper pinion depth. I don't think the perfect pattern is that critical. I personally like the drive side a little towards the toe and the coast side a little towards the heel when I take my pattern.
Faulty diagram. The pinion itself and the conical bearings, on each end of the pinion, have to have zero clearance or the pinion would tilt up or down randomly during use. Therefore all in and out play at the drive shaft flange must be zero clearance to cause each cone inner bearing to ride straight on the races. So that is an absolute that must be addressed and the location of pinion teeth with the ring gear would have to be done with a pinion that extended farther in its length by the machining maker or a ring gear that had teeth that extended farther inward. But you cannot have in and out play at the flange at the nut
Yes of course the pinion bearings have to have a preload so there is no movement. The diagram is not faulty and it serves an accurate representation for the purpose of the explanation of pinion depth what it is and how the contact patch is impacted by correct and incorrect pinion depth.
@@DrivelineMaster Yes, but after the intitial adjustment of pinion flange preload, the fact that the teeth on the pinion dont match up with the ring gear is still not adjustable as the diagram tries to represent, meaning its a useless faulty diagram made by a person that sits behind a desk. The only adjustment at the ring gear is shims or a different ring gear altogether. Its still a fictional diagram. You need to read again my comment. There is no way you can correct the pinion depth once any end play is gone. Cant you understand this?
@@EarlGuyton425 I believe I do understand you point. When the depth increases the animation leaves a large gap so the ring gear teeth don't touch and of course when pinion depth is reduced the pinion would jam into the ring gear. I as well as you know that pinion movement is done without the ring gear and case installed. then after the pinion is in the ring gear location and backlash can be adjusted. I didn't take the time to make the animation that complex plus the idea was to get across the concept of what pinion depth was and I wasn't so worried about that part of the animation. Maybe I should have. This has been up for a long time and a lot of experienced technicians have viewed it without complaint. Yes, the animation and graphics could be more accurate. I'm a self taught graphics and animation person and this is what I came up with and I still think it's pretty good at explaining pinion depth.
@@DrivelineMaster The diagram doesnt show/inform that ring gear tooth adjustment also has to be done by adding or removing shims at the bearings on the sides or shims behind the ring gear. Thats why I see it as a fictional diagram, because the novice will be led to believe that the pinion itself can be further out or inward without regard to the end play fixed necessary position. The maker of the video diagram Was probably done by a novice individual that sits behind a desk that took an original blue print machining sheet and made it appear that there is a pinion adjustment and ring gear adjustment. The original blue print they worked off of required no adjustment at all. To make a pinion assembly go inward or outward more would requiring the machining of a totally different pinion that was shorter or longer and that wouldnt be necessary because the original blue print shows the allowed clearances. So why is or was this diagram made which will only cause false believe in the minds of your average person. The mind of the novice will now believe, Oh no I better measure the clearance where the end of my pinion is next to the hub now, when in reality that assembly with its pinion sleeve and washer behind the rear pinion cone bearings are a fixed pre measured assembly as in these are not things any person is going to have to worry about or ever do.
One thing that needs to done is to put the crown wheel under some load a crow bar forcing down on the wheel between the case and coat 6/7 teeth with paste and turn the pinion twenty plus times that will give a real good marking and a bit less paste, engineers blue can be used for marking too,
One thing that I forgot to show was that I did do that. I formulated a section of brake pad onto a bracket with a pressure adjustment screw so the crown gear or ring gear as we call it was under pressure. I just didn't show that because the focus of the video was on what happens to the pattern as the depth is changed.
Very good. but it's not so easy on old jeep Salisbury diffs. To adjust pinion and backlash, you have to remove the guts, and pull off the usually very tight tapered bearings, then add or subtract shims, put the thing back together again, check the contact pattern, and if necessary (usually), pull the whole thing apart again, remove bearings, add or subtract shims..ad nauseum. Thank goodness for the screw in type bearing adjusters.
Yes, there is a bit of trial and error involved and some are harder to do than others. That is why knowing if you add or subtract is important. Nobody wants to go through all that work only to find out that you added when you should have subtracted. If you do this on a frequent or semi-frequent basis I suggest buying a pair of bearings for the diff and use a small cylinder hone to remove a little of the metal from the inside of the inner bearing race so the bearings just slide on with no wiggle room. That way you won't have trouble removing the tapered bearings. After you know which shim produces the correct contact patch replace the modified bearings with new bearings with a tight fit. Save the modified bearings for the next job. PS. Make sure to thoroughly wash the modified bearings after honing and lightly oil them before using them to setup your pinion depth.
Think of it as the measured value. The closer the pinion is to the center of the differential the smaller the distance and therefore pinion depth is reduced. It's more of a perspective than counterintuitive.
Yes there will be a minor change due to heat expansion. The backlash is more likely to change but the depth is not likely to change. I doubt the contact patch would change enough to see or measure it. Of course the higher the heat the more likely the change.
I once took a factory Ford class on Diff setup and I was told not to worry about the contact patch. As long as I used their pinion depth tool correctly, OEM gears and set the backlash was set correctly I didn't need to worry about the contact patch. Because of variations in gear machining I disagreed and feel that the contact patch is the final say in confirming the setup was correct.
Yes, You are correct. The cut away I used had a friction shoe pressing on the ring gear that you could not see as I turned the pinion. When I do this on the workbench or on the car I rotate the ring gear and apply rotational friction to the pinion. One easy way to do this is to enlist an aid. Wrap a shop rag around the pinion just under the flange. Have the assistant pull on the rag to create rotational friction to the pinion. This can make it impossible to turn the ring gear so the assistant needs to give a little on the force just enough to allow you to turn the ring gear. I hope this made sense. The greater the load the better the contact patch you will get.
@@DrivelineMaster That makes total sense to me. I really appreciate your help and video. I'm currently restoring a 1970 Mercedes 6.3. As I'm sure you know the rear end of a Mercedes of this era is a little different, but I'm assuming all the principle's you spelled out apply. I may message you from time to time if that's ok:)? Thanks once again for your video. Cheers John.
It took me a bit to figure out what you are pointing out. I believe you are calling the ring gear the crown wheel. Am I correct. I think also what you are saying is that the coast side is actually driven when the vehicle is coasting as the drive wheels drive the case and ring gear which in turn drives the pinion gear. I have done the pattern both ways for drive and driven and several service manuals and aftermarket gear manufactures will turn the pinion forward and reverse or they will turn the ring gear forward and reverse. I have done this both ways and the results seem to be the same. The key factor is adding resistance to the rotation. this ensures the paste wipes off correctly.
DrivelineMaster thank you for a very informative video. Yes I called the ring gear the Crown gear I also called Coast side overrun side overrun occurs when the power train is working backwards being powered by the back wheels of the car
Good visuals & I already understand the importance & meaning of pinion depth. Big problem, how do you find the dimension you need? On GMs the value is stamped on the end of the pinion gear, on others (Chrysler 9 1/4 for example) this measurement seems to be a military secret. Where is the info? Give your audience info on something other than a GM product.
The fact of the matter is that most OE manufactures will provide you with the actual depth measurement. If you buy an aftermarket gearset the depth will be marked on the pinion head. I think the reason is that most OE don't measure the exact depth but instead the OE depth gauge is more of a tool used to find the shim thickness instead of the actual depth. The technician uses the OE tool which provides an answer in thousandth of an inch as to the size of the shim to use. I guess they felt the technician wouldn't be able to do a little math. In most cases if you are staying with the OE gear ratio or very close to it I use the OE shim that was in the original gearset and I test the pattern and adjust from there adding or taking away shim thickness. Do another pattern and adjust again if needed. I can normally dial it in within 1 - 3 tries.
@@DrivelineMaster I have never done a ring & pinion change or an R&R of the diff bearings. Currently doing the R&R of bearings on a 9 1/4 Chrysler so I'm going to just put everything back as it came out & hope for the best. I'm doing my own because the guy that I once used has retired & his replacement is unreliable. I have been researching the process & watching videos & from what I have seen the process seems to be more trial & error than a technical process. The problem w/ the 9 1/4: if you change the ring & pinion from one axle assy to another there are no markings on the end of the factory pinion, it's just rough casting w/ no dimensions anywhere. I am a retired machinist & have the ability to measure things very accurately & can handle the math. My job required me to solve dimension problems using plane trig & hold tolerance to + or - .0005". Measuring is no problem but I have to have a starting point. From everything I have read & studied there are 2 different tolerances to consider: The + & - tolerance of the machining of the axle case (the shoulder where the rear pinion brg race seats) and the + & - tolerance machined in the pinion gear itself. As a machinist I can tell that the bearing race seat in the case is not an accurate surface by the machine marks. To hold a close tolerance the shoulder would have to be a ground (process done w/ an I.D. grinder) surface & it is not. On the 9 1/4, I have 2 factory gear sets & neither has any dimension markings on the end of the pinion. I'm still doing research because I plan on doing another one later. Thanks for the reply & sorry about the length of my reply.
Hi Larry, No need to worry about the exact number for the pinion depth. You are correct that the OEM does not mark the depth on the pinion like aftermarket gearsets do. You might have to do a little trial and error to setup the depth but it's not too difficult if you understand depth and contact patch. Watch my video on pinion depth and contact patch for that explanation. Start with the original size pinion depth shim. Put everything together except leave out the pinion bearing crush sleeve, pinion seal and don't use the new pinion nut. Carefully tighten the pinion bearing preload to approximately what it should be. Normally around 20" lbs. of breakaway rotational force. Use contact paste or other suitable compound on 3 - 4 ring gear teeth. Use the contact patch on the drive side ring gear tooth to determine if you need to adjust the depth or leave it alone. if the contact is too close to the toe you need more depth. If the contact is too close to the heel you need less depth. Adjust the shims accordingly. There is a little trick for those who build a lot of diffs. Depending on where the depth shims go (between the rear race and housing or between the pinion head and the rear bearing) a spare bearing is purchased or an old one is used if it is in good shape. If the shim goes under the outer race a small amount of material is removed from the outside circumference of the spare bearing race. Just enough to remove the interference fit and the race just barely slides into the housing making shim changing quick and simple. The same can be done from the inside diameter of the rear bearing where it fits on the pinion if the shims go there. Please note that after getting the correct shim do not use the bearing that was modified. Use the new bearing and race that will still have the interference fit. When you are ready for the final assembly use the crush sleeve, pinion seal and new pinion nut. If you really want a depth number there is something called a Master Housing Depth (MHD). This value, if you can obtain it is used along with the size of your pinion head to determine the pinion depth. If you want, I might have the master housing value at work. Just know my final decision is always the contact patch so even if I use a depth gauge. If the pattern is off I adjust the depth based on the contact patch. If I remember I will try to find the MHD next week for a 9 1/4" Chrysler and send it to you along with the procedure.
Thanks for the info. i'm resigned to the fact that there is going to be quite a bit of trial & error involved it's just that I'm not used to that sort of thing. I have built many engines & trans & usually have definite specs to work with. That MHD you refer to would be help if things don't go well on the first try. I'm using the original brand bearings so I should be able to get very close on the first try. The pinion depth on the 9 1/4 is set by a shim under the rear bearing (between the bearing & the pinion gear head). I have already pressed the bearing in place so if the gear contact is off I will have to buy a couple more bearings to do the set up. Is there any specified amount of shim to either remove or add based on where the gear contact is located? For example: if the contact is real close to the heel or toe & has to move approx 1/2" to get centered what amount of shim change would get the desired result? There probably is no standard due to the various sizes of the ring & pinion sets but some approx would be helpful. I have made some tools to get the job done. One U tube video showed how to make a carrier bearing adjusting nut tool for the 9 1/4 using a common & cheap hardware store item. I have also made sleeves to press bearings in place. One sleeve is to pull the pinion through the fwd bearing without using the pinion yoke. Frustration w/ the factory shop manual (FSM) is another factor. It says that there are set up markings on the head of the pinion and there are not. Also, the preliminary torque value for the pinion pre load is not accurate. That value is 210" lb & is way too much. Produces over 60" lb drag on the pinion. Again, thanks for taking the time to reply, it's appreciated.
Glad to help. I found the T&D depth tool instructions online. They explain how to calculate pinion depth using the MHD and they also provide the MHD for your 9.25 diff. I have inserted the link below. Unfortunately I have discovered over the years that each diff responds differently to pinion depth .010" shim change. it seems smaller diffs are more sensitive than larger diffs when changing pinion depth shims. If I need to make a change I usually start with a .010" shim change and see how much the pattern moves and adjust from there. Does this diff use a pinion crush sleeve or shims to adjust pinion bearing preload. The reason I ask is because the pinion nut tightening value is not normally given in foot pounds. Normally it's given in rotational force on the bearings. If you have a foot pound specification it might mean that your pinion bearing preload is adjusted using shims between the front bearing and a shoulder on the pinion. If so, you can torque to the 210' lbs and still obtain the correct rotation force just by adjusting preload shims. One last note. If you have a press and a good bearing splitter it is often possible to remove the rear bearing from the head of the pinion without damaging it. Additionally, being a machinist you could manufacture a clam shell tool to pull the bearing off without damaging it. www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwiY2ej9ntXrAhXmHjQIHa7aC14QFjAAegQIAxAB&url=http%3A%2F%2Ftdmach.com%2Fwp-content%2Fuploads%2F2018%2F01%2FDeluxe-Pinion-Checker-11148.pdf&usg=AOvVaw3d3eEiKFZ0lT4JLCdlFVKH
If only all videos were this clear, concise, and well done. The old saying is "A picture's worth a thousand words" and this animation is worth a lot more than that. Fantastic job DLMaster!
Actually its a faulty diagram. Read my comment above of why this is. Faulty diagram. The pinion itself and the conical bearings, on each end of the pinion, have to have zero clearance or the pinion would tilt up or down randomly during use. Therefore all in and out play at the drive shaft flange must be zero clearance to cause each cone inner bearing to ride straight on the races. So that is an absolute that must be addressed and the location of pinion teeth with the ring gear would have to be done with a pinion that extended farther in its length by the machining maker or a ring gear that had teeth that extended farther inward. But you cannot have in and out play at the flange at the nut
Hands down, the BEST video on YT explaining the principles of diff adjustments. In 7 minutes and 16 seconds this man achieved what others couldn't achieve in hours of screen time!!!
Thanks, My goal is Short, sweet and too the point with quality video and audio.
I don’t get it!! He change the adjustment and return to 10 and got different backlash!!!!!
I changed the depth adjustment which changed the backlash. I reset the backlash to .010" and retested the contact patch which moved slightly. What don't you get? I'm willing to explain it.
This s a subject I've always wanted more about. Thank You for the clear, no music explanation. JD
Agreed, best demonstration of pinion depth and backlash I’ve seen. Thank you
I overhauled a lot of differentials in the past; and your video hits the mark. Most people don't understand how precise the set-up has to be; and how a very very small miscalculation can cause all types of drivability issues.
Thanks
Should emphasize the fact that contact patch and backlash should be checked with the axles in the differential (loaded) and tires on to offer some resistance in drive and coast.
Thank you for your comment and observation. The axles do not have to be in and in this removable design that is really difficult. It is very important to provide a load or resistance to rotation to obtain a good contact patch pattern. What you can't see so well is I built in a braking mechanism that is applying rotational resistance to the ring gear. This is adding enough load to provide a good pattern. The objective of this video was not to show how to perform a contact patch pattern but instead to explain how the pattern is effected by the change in drive pinion depth.
best explaining video on youtube until now !!!!
Putting gears in a friend's Jeep. Set this video to him so he can better understand what I'm doing. To the point and clear explanation! Thanks
perfect this is what i call a mechanical service well done congratulations
Finally, someone giving perfect explanation to pinion depth on a 9 inch style diff. Thank you.
This really applies to all differential designs however the 9" style was much easier to make an adjustable pinion to demonstrate the effects pinion depth has on a contact patch.
This is then best vid on showing how to make diff adjustments. Thank you ! I have wondered for years about this!
this is the best video i’ve seen on youtube explaining how all this works in great detail!
Masterclass. Like a video game from the 90s you subtly explained the vocab needed to win
Iv never rebuilt a rear differential before but I’m going to have to rebuild the rear differential in my 96 Ranger Splash. This video helps me a lot and gives me the confidence that I can do it!
Thank you!
Glad I could be of help. Don't hesitate to reach out if you need additional info or help.
what a GREAT explanation of what's going on with the gears - ESPECIALLY with the visual aid! thank you!
I'm no mechanic and I....... even got an understanding of the process. The best explanation I've seen yet.
:)
Good information. I've had production experience setting up construction equipment spiral bevel gears, same system applies. A little toe bearing centered up is acceptable as opposed to heel bearing. The toe of the ring tooth being thinner will flex and spread increaseing the load bearing pad back towards the heel.
You are correct.
Pretty clear and educative. I have learnt 2 ways of differential gear adjustment from you, i.e using dial gauge measurement and contact marker visual inspection. Thanks!!
The Dial indicator is measuring Ring to Pinion gear backlash (clearance)
The gear contact paste, is indicating Pinion gear engagement depth with the ring gear.
Two very different measurements...
What you are not told is in order to setup a pinion on an 8.8 Ford, it requires the purchase of an extra (setup) bearing, identical in manufacturer to the bearing you will finally use. This bearing must be modified to "slip fit" on to the pinion so pinion depth can be setup. Additionally, you will need a few extra crush sleeves for this process...
great explanation - and a BIG thank you for NO background music. I hate it when presenters do that.
This is exactly what I was looking for thank you so much! I feel like I’m in class you’re a good teacher
Thanks. I'm glad you enjoyed it and found value. Your comment mirrored 99.99% of the comments for this video. My videos are all from and educational perspective with an emphasis on quality video and audio with the smallest length possible and to be concise, complete, and accurate as possible.
This is a very clear and useful explanation of an important topic. I'm really happy that you published this piece. Thanks.
Excellent video explaining Ring and Pinion gear relationship. The most helpful to me was the use of gear contact paste on just two teeth. I see other videos where its slopped all over the entire ring gear. Your approach makes better sense.
My factory training taught me to paste every tooth and it can revel some information about the setup however in real life I paste 4 teeth every 90 degrees. This gives me a feel for the setup.
Nice! Wish my Ford 9" pinion was that easy to adjust, but I get the concept totally. Thank you.
Excellent video, demonstration and animations. Thank you!
Thanks. I do NDT in a shop that repairs speed reducers but don’t know much about their operation. So this is what the assemblers are doing when they have a gear set together but keep tinkering with it.
Most likely.
Thank you for your knowledge and you willing to share this information 👍
Have a bless day
This video is great and helps a lot. The only thing I don't understand is when you say you have to move the pinion gear father away from centerline, I don't know which way you're moving it because I can't see it moving in the video.
Watch from timestamp 0:26 to 0:31 and 1:16 and 1:22. The pinion moves to the left but I don't like to say to the left because what would happen if the image was flipped 180 degrees or even just 90 degrees. So it's not a good idea so say the pinion moves left, right, up or down but instead talk about in relationship to the centerline of the ring gear.
@@DrivelineMaster
I'll try to look again, maybe I can watch the video on a 65 inch TV. Thank you
might be hard to see on a phone with a small screen but any monitor larger than 13 inches should be large enough to see the movement.
Excellent video. Very well shown and edited, short and awesome. Thank you, Jim H.
I try to do this with all my videos.
I tried your suggestion with that "straddle mount" during a third date. It didn't go well. And I assure you my pinion shaft was large enough even though my date didn't think so. Just saying. But thank you for the video. It was worth a try. You RoCk!
Thankyou! And shown with a 9" diff too, my fave 🙂 Doesn't get better than that!
Great explanation on set up.very good explanation.
Fantastic information. Just what I was looking for!
It looks like I Finally understood the assignment after watching this video, thanks C ñor 😊
A very well put together video, thank you.
Alway well explained and illustrated! Love this channel!
Liked the video before I even watched, knew it was going to be helpful based off the thumbnail
I'd like to see you continue moving the pinion away from the ring or "increasing the pinion depth" until the pattern went unacceptable the other way.
I just set up my Toyota 8" and the drive pattern you found acceptable I had at one point, but when I read the pinion teeth it was showing a shallow mesh leaning towards the diff centerline or toe (this is a rockcrawler) - so I pulled another .010" from the pinion head stack and ended up with a nicely centered oval drive & centered comet tail pinion pattern - but my coast pattern still looks similar to your drive pattern and I'm not sure why.
Your drive side pattern is your most important and the biggest goal is to make sure the pattern is not running off the toe, heel, face or too deep into the flank. It would be great if drive and cost would always both be perfectly centered but that is rare. In fact I prefer the drive side to be slightly towards the toe and coast to be slightly towards the heel. I do this because under heavy load the pinion will thrust slightly towards the front of the vehicle causing the drive and coast side patterns to center. If you are working on a front diff and it's flipped so the pinion centerline is above the axle like front diff's on 4x4's offend are for ground clearance the drive and coast sides of the ring gear are reversed. The drive side is concave and the cost side is convex. I hope this helps.
Finally I can understand this.. reading from a book just doesn't make sense in my head. Thanks for the visual!
Glad this helped
very good video training ,clear explained easy to understand ,thanks
Excellent demonstration! Thanks you!
Great Video.. No music thanks.. just great information..
Very clear video in showing relative positioning and optimal settings checks.
Could this test determine if a used pinion gear/ring gear combination , has been worn beyond suitability for reinstallation practicality ?
severely worn ring and pinion sets are normally noticeable by visual inspection however they will often exhibit patterns that look like thin lines as compared to oval or triangular shaped.
DrivelineMaster
Thank you for your reply!
I will bring this ; and use it.
Teach it;also.
Perfect explanation and demonstration. A+
Excellent explanation. Hard to get better than this.
This is a great explanation. My students will benefit from this as well. Thank you again. I enjoyed your presentation at ATRA this past October.
Thank you stay safe and healthy
Awesome video. Great for ASE prep
Wish all differentials used this adjustment features. Way easier to set up. Modern truck differentials aren't this way at all on adjusting easily.
Very nice presentation making process understandable. Thank you!
WOOHOO more information differentials :D Loving it, keep up the great work DrivelineMaster! Visual is always nice!
Great instructional video, thank you!
Your Welcome
Thanks for the clear info!! My 12 bolt thanks you!
this video doubles as a relaxation / sleep video!
Well......... if your not interested no one is forcing you to watch.
@@DrivelineMaster actually it was a compliment, very relaxing voice!
Sorry for the reaction. I thought I was boring you.
This is stellar, "DrivelineMaster", obviously.
Excellent video. I’d thin that compound with gear oil for a much nicer and more detailed pattern indication.
Awesome! Thank you for video.
Excellent very educative and informative thanks.
Very clear. Very useful. Many thanks!!
sehat selalu master.. terimakasih ilmunya
Subscribed, after watching this masterpiece
Nice job Friend
Thanks so much for the video! It really made it clear for me. I was wondering if a used rear axle was making noise from say too much back lash, could it be made quiet again by making the right adjustments to the back lash/wear pattern? Or would you have to rebuild the rear end and get a new gear set? The rear axle has 120,000 miles on it and the teeth on the gear do not "look" bad.
If you are getting clucking from too much backlash especially when switching from D - R or R to D you most certainly can change the backlash adjusters (Shims or Threaded Adjusters) to correct or reset the backlash. You won't need to mess with pinion depth and you should not have to worry about contact patch. As long as you have the dial indicator and the tools and methods to make the adjustment. Just make sure to check your backlash in at least 6 to 8 different locations around the ring gear and make sure the backlash is never smaller than the minimum specification. If your getting humming or moaning noises that is not a backlash noise and readjusting the Backlash will not fix this type of noise.
@@DrivelineMaster the noise I am getting is a moaning noise from about 30 mph on up. It moans when I am on the gas. If I let off the gas and coast it gets a lot quieter. I changed both rear axle bearings as on side was bad. I didn't see any play in the pinion bearing and it spun freely. There were no visual defects in either gear. What do you think is the cause? Thanks in advance
This is a description of a classic rear drive pinion bearing noise. Sometimes worn gears will do this but it's not as common as a pinion bearing. Normally if it's gear noise you can't see the wear but a contact patch can sometime identify worn gears. The contact patch should be non symmetrical triangular or oval. Normally if the gears a bad the contact patch will be a straight thin line. Place a listening device such as a mechanics stethoscope or you can use a screw driver or extension bar up to your ear while holding the other end against the differential housing in different locations. Once near the rear pinion bearing and once near the front pinion bearing. Do this with the wheels off the ground and someone driving the vehicle accelerating and decelerating as you listen. I put 95% chance your problem is the rear pinion bearing even if rotation feels smooth when turning it by hand.
@@DrivelineMaster Thank you for your detailed advice!!!!!
Best vid yet 👍
Are these gears face hobbed or face milled? Also does that actually even matter when checking patterns? I've been trying to learn all I can when it comes to setting rears up, love this demonstration!!
I believe this is a face milled Five-cut gear set. If you have been doing some research then you most likely found this URL. gearsolutions.com/features/face-off-face-hobbing-vs-face-milling/
also this from Yukon gear
www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwif_e-JxbL0AhXloFsKHYN6DQ0QFnoECAIQAQ&url=https%3A%2F%2Fwww.yukongear.com%2Fweb_images%2Fpages%2FBrochures%2F2-Step-vs-5-Step-Gears.pdf&usg=AOvVaw2q8lfMkwNzdKq7Hzfd8FJ-.
The pattern is different and moves across the tooth differently depending on how it's cut.
Great sir very informative 👍
Amazing Bravooo
So what were you adjusting everytime you had to move the backlash back to 10 thousands ? How do you read the number on the pinion gear to determine what shim pack is best and closest to start with? If it's a minus number foes that mean you need to add shims to bring it forward to the ring gear or have less shims to move it down to that measurement from the centreline?
Great Video very informative thanks
Nice vid explains a lot I have a better understanding of contact patch but what happens if one side is ok but the over drive side (back side is off ) how would the adjustment be made ?
The drive side of the ring gear tooth is always the pattern of most concern. If the coast side is off a bit I don't worry too much as long as the drive side is where I want it. Two other factors effect contact patch. Backlash and worn gears. Although Backlash effects the pattern differently (hey, that give me an idea on a new video) worn gears will create all kinds of weird patterns that won't make any sense.
Love this video! Very good information!
I'm glad. My goal is quality training video's.
Very good video. Would it be possible to place a link of the tools you used in the discretion? Thanks
The dial indicator is a standard 1" dial indicator. For in the shop I normally use one that can be setup using vise grip locking pliers similar to this Central tool. store.dealershopusa.com/product_info.php?products_id=77440&gclid=EAIaIQobChMI1sHB_4Gd_gIVkR-tBh0ZUwCtEAQYBiABEgJLgPD_BwE The spanner nut wrench is a Mazda specialty tool that is adjustable making it universal but I don't think it can be purchased anywhere except from a Mazda specialty tool store. To perform the contact patch watch this video. ua-cam.com/video/UIIk305-zlQ/v-deo.html. To adjust backlash watch this video. ua-cam.com/video/d9cxw9d-css/v-deo.html. If you would like to Mazda spanner nut tool number write back and I will look at the tool one day next week and write you back.
@DrivelineMaster I would like to get into differential rebuild. Most people remove the pinion and check. I notice he didn't do that. He was using a tool to adjust the depth and lash. I'm interested in that tool also. Was that the Mazda tool you mentioned? Thanks
The Mazda tool was the spanner wrench that I used to adjust the backlash. I did not use a tool to change the depth. Instead I customized that differential to allow me to change the depth just by turning a threaded rod. For all other applications pinion depth is adjusted by disassembling the differential and changing a shim thickness. I also have a video on how to use a pinion depth measurement tool. You might want to look at these two video's. ua-cam.com/video/gk6imita0cc/v-deo.html and ua-cam.com/video/QL-dmhfSj6k/v-deo.html and these two as well. ua-cam.com/video/_bUh9NEMldI/v-deo.html and ua-cam.com/video/bxi7EiQzo9E/v-deo.html
Great video
Thank you
Excellent video
Thanks
Gotta love the Ford 9"
God yes...I've got a Dana 44 I need to do and I'm dreading it.
Nice and clear to understand , thanks
Exellent learning tool!!
I like the way this video got right to the point . I'm going to Delete some of my other videos that are too long-winded.
Thank you for noticing. That is one of my goals along with; Short, clear, informative, accurate and quality.
This is excellent!
Well explained.. now please come and setup my 911 gearbox :)
Very good and helpful video
Subscribed;
You are the Master, great explanation; just out of curiosity what would it take to get a perfect pattern on both sides,and is it possible? and any advantage to doing that,just for (heavy,towing etc ) street use?
It does happen but not as often is I would like. Start with a case with zero axial run out. Add a quality gear set with tight tolerances. Have it assembled by someone who takes a lot of care and attention to details. Finally the proper pinion depth. I don't think the perfect pattern is that critical. I personally like the drive side a little towards the toe and the coast side a little towards the heel when I take my pattern.
@@DrivelineMaster Thanks.
amazing video.so thanks. do u have video about adjust preload of bearing of penion ?
Wow this is a great video thanks
Faulty diagram. The pinion itself and the conical bearings, on each end of the pinion, have to have zero clearance or the pinion would tilt up or down randomly during use. Therefore all in and out play at the drive shaft flange must be zero clearance to cause each cone inner bearing to ride straight on the races. So that is an absolute that must be addressed and the location of pinion teeth with the ring gear would have to be done with a pinion that extended farther in its length by the machining maker or a ring gear that had teeth that extended farther inward. But you cannot have in and out play at the flange at the nut
Yes of course the pinion bearings have to have a preload so there is no movement. The diagram is not faulty and it serves an accurate representation for the purpose of the explanation of pinion depth what it is and how the contact patch is impacted by correct and incorrect pinion depth.
@@DrivelineMaster Yes, but after the intitial adjustment of pinion flange preload, the fact that the teeth on the pinion dont match up with the ring gear is still not adjustable as the diagram tries to represent, meaning its a useless faulty diagram made by a person that sits behind a desk. The only adjustment at the ring gear is shims or a different ring gear altogether. Its still a fictional diagram. You need to read again my comment. There is no way you can correct the pinion depth once any end play is gone. Cant you understand this?
@@EarlGuyton425 I believe I do understand you point. When the depth increases the animation leaves a large gap so the ring gear teeth don't touch and of course when pinion depth is reduced the pinion would jam into the ring gear. I as well as you know that pinion movement is done without the ring gear and case installed. then after the pinion is in the ring gear location and backlash can be adjusted. I didn't take the time to make the animation that complex plus the idea was to get across the concept of what pinion depth was and I wasn't so worried about that part of the animation. Maybe I should have. This has been up for a long time and a lot of experienced technicians have viewed it without complaint. Yes, the animation and graphics could be more accurate. I'm a self taught graphics and animation person and this is what I came up with and I still think it's pretty good at explaining pinion depth.
@@DrivelineMaster The diagram doesnt show/inform that ring gear tooth adjustment also has to be done by adding or removing shims at the bearings on the sides or shims behind the ring gear. Thats why I see it as a fictional diagram, because the novice will be led to believe that the pinion itself can be further out or inward without regard to the end play fixed necessary position. The maker of the video diagram Was probably done by a novice individual that sits behind a desk that took an original blue print machining sheet and made it appear that there is a pinion adjustment and ring gear adjustment. The original blue print they worked off of required no adjustment at all. To make a pinion assembly go inward or outward more would requiring the machining of a totally different pinion that was shorter or longer and that wouldnt be necessary because the original blue print shows the allowed clearances. So why is or was this diagram made which will only cause false believe in the minds of your average person. The mind of the novice will now believe, Oh no I better measure the clearance where the end of my pinion is next to the hub now, when in reality that assembly with its pinion sleeve and washer behind the rear pinion cone bearings are a fixed pre measured assembly as in these are not things any person is going to have to worry about or ever do.
Excellent!... much thanks.
One thing that needs to done is to put the crown wheel under some load a crow bar forcing down on the wheel between the case and coat 6/7 teeth with paste and turn the pinion twenty plus times that will give a real good marking and a bit less paste, engineers blue can be used for marking too,
One thing that I forgot to show was that I did do that. I formulated a section of brake pad onto a bracket with a pressure adjustment screw so the crown gear or ring gear as we call it was under pressure. I just didn't show that because the focus of the video was on what happens to the pattern as the depth is changed.
Good yes the best informition
Great video!
Very good. but it's not so easy on old jeep Salisbury diffs. To adjust pinion and backlash, you have to remove the guts, and pull off the usually very tight tapered bearings, then add or subtract shims, put the thing back together again, check the contact pattern, and if necessary (usually), pull the whole thing apart again, remove bearings, add or subtract shims..ad nauseum. Thank goodness for the screw in type bearing adjusters.
Yes, there is a bit of trial and error involved and some are harder to do than others. That is why knowing if you add or subtract is important. Nobody wants to go through all that work only to find out that you added when you should have subtracted. If you do this on a frequent or semi-frequent basis I suggest buying a pair of bearings for the diff and use a small cylinder hone to remove a little of the metal from the inside of the inner bearing race so the bearings just slide on with no wiggle room. That way you won't have trouble removing the tapered bearings. After you know which shim produces the correct contact patch replace the modified bearings with new bearings with a tight fit. Save the modified bearings for the next job. PS. Make sure to thoroughly wash the modified bearings after honing and lightly oil them before using them to setup your pinion depth.
Great video, never seen that paste I use blu
it seems counterintuitive to measure pinion depth such that when you push the pinion deeper into the differential, pinion depth is reduced.
Think of it as the measured value. The closer the pinion is to the center of the differential the smaller the distance and therefore pinion depth is reduced. It's more of a perspective than counterintuitive.
Couldn't be any better
Excellent vedio
Thanks for the video!
good presentation
I'd be curious to heat up the components to operating temperature and check if that affects the contact point.
Yes there will be a minor change due to heat expansion. The backlash is more likely to change but the depth is not likely to change. I doubt the contact patch would change enough to see or measure it. Of course the higher the heat the more likely the change.
Send this to FORD they have a lot to learn.
I once took a factory Ford class on Diff setup and I was told not to worry about the contact patch. As long as I used their pinion depth tool correctly, OEM gears and set the backlash was set correctly I didn't need to worry about the contact patch. Because of variations in gear machining I disagreed and feel that the contact patch is the final say in confirming the setup was correct.
Nice video...
When you are testing the contact patch (by turning the ring gear) doesn't it have to be under some load? Thanks for the video.
Yes, You are correct. The cut away I used had a friction shoe pressing on the ring gear that you could not see as I turned the pinion. When I do this on the workbench or on the car I rotate the ring gear and apply rotational friction to the pinion. One easy way to do this is to enlist an aid. Wrap a shop rag around the pinion just under the flange. Have the assistant pull on the rag to create rotational friction to the pinion. This can make it impossible to turn the ring gear so the assistant needs to give a little on the force just enough to allow you to turn the ring gear. I hope this made sense. The greater the load the better the contact patch you will get.
@@DrivelineMaster That makes total sense to me. I really appreciate your help and video. I'm currently restoring a 1970 Mercedes 6.3. As I'm sure you know the rear end of a Mercedes of this era is a little different, but I'm assuming all the principle's you spelled out apply. I may message you from time to time if that's ok:)? Thanks once again for your video. Cheers John.
Yes you can email for advice. The principles are the same. I don't have much vintage Mercedes experience.
@@DrivelineMaster Thank you very much. I really appreciate that.
One small point you showed contact area in drive and reverse gear for coast side you should've driven the crown wheel
It took me a bit to figure out what you are pointing out. I believe you are calling the ring gear the crown wheel. Am I correct. I think also what you are saying is that the coast side is actually driven when the vehicle is coasting as the drive wheels drive the case and ring gear which in turn drives the pinion gear. I have done the pattern both ways for drive and driven and several service manuals and aftermarket gear manufactures will turn the pinion forward and reverse or they will turn the ring gear forward and reverse. I have done this both ways and the results seem to be the same. The key factor is adding resistance to the rotation. this ensures the paste wipes off correctly.
DrivelineMaster thank you for a very informative video. Yes I called the ring gear the Crown gear I also called Coast side overrun side overrun occurs when the power train is working backwards being powered by the back wheels of the car
Good visuals & I already understand the importance & meaning of pinion depth. Big problem, how do you find the dimension you need? On GMs the value is stamped on the end of the pinion gear, on others (Chrysler 9 1/4 for example) this measurement seems to be a military secret. Where is the info? Give your audience info on something other than a GM product.
The fact of the matter is that most OE manufactures will provide you with the actual depth measurement. If you buy an aftermarket gearset the depth will be marked on the pinion head. I think the reason is that most OE don't measure the exact depth but instead the OE depth gauge is more of a tool used to find the shim thickness instead of the actual depth. The technician uses the OE tool which provides an answer in thousandth of an inch as to the size of the shim to use. I guess they felt the technician wouldn't be able to do a little math. In most cases if you are staying with the OE gear ratio or very close to it I use the OE shim that was in the original gearset and I test the pattern and adjust from there adding or taking away shim thickness. Do another pattern and adjust again if needed. I can normally dial it in within 1 - 3 tries.
@@DrivelineMaster I have never done a ring & pinion change or an R&R of the diff bearings. Currently doing the R&R of bearings on a 9 1/4 Chrysler so I'm going to just put everything back as it came out & hope for the best. I'm doing my own because the guy that I once used has retired & his replacement is unreliable. I have been researching the process & watching videos & from what I have seen the process seems to be more trial & error than a technical process. The problem w/ the 9 1/4: if you change the ring & pinion from one axle assy to another there are no markings on the end of the factory pinion, it's just rough casting w/ no dimensions anywhere. I am a retired machinist & have the ability to measure things very accurately & can handle the math. My job required me to solve dimension problems using plane trig & hold tolerance to + or - .0005". Measuring is no problem but I have to have a starting point. From everything I have read & studied there are 2 different tolerances to consider: The + & - tolerance of the machining of the axle case (the shoulder where the rear pinion brg race seats) and the + & - tolerance machined in the pinion gear itself. As a machinist I can tell that the bearing race seat in the case is not an accurate surface by the machine marks. To hold a close tolerance the shoulder would have to be a ground (process done w/ an I.D. grinder) surface & it is not. On the 9 1/4, I have 2 factory gear sets & neither has any dimension markings on the end of the pinion. I'm still doing research because I plan on doing another one later. Thanks for the reply & sorry about the length of my reply.
Hi Larry, No need to worry about the exact number for the pinion depth. You are correct that the OEM does not mark the depth on the pinion like aftermarket gearsets do. You might have to do a little trial and error to setup the depth but it's not too difficult if you understand depth and contact patch. Watch my video on pinion depth and contact patch for that explanation. Start with the original size pinion depth shim. Put everything together except leave out the pinion bearing crush sleeve, pinion seal and don't use the new pinion nut. Carefully tighten the pinion bearing preload to approximately what it should be. Normally around 20" lbs. of breakaway rotational force. Use contact paste or other suitable compound on 3 - 4 ring gear teeth. Use the contact patch on the drive side ring gear tooth to determine if you need to adjust the depth or leave it alone. if the contact is too close to the toe you need more depth. If the contact is too close to the heel you need less depth. Adjust the shims accordingly. There is a little trick for those who build a lot of diffs. Depending on where the depth shims go (between the rear race and housing or between the pinion head and the rear bearing) a spare bearing is purchased or an old one is used if it is in good shape. If the shim goes under the outer race a small amount of material is removed from the outside circumference of the spare bearing race. Just enough to remove the interference fit and the race just barely slides into the housing making shim changing quick and simple. The same can be done from the inside diameter of the rear bearing where it fits on the pinion if the shims go there. Please note that after getting the correct shim do not use the bearing that was modified. Use the new bearing and race that will still have the interference fit. When you are ready for the final assembly use the crush sleeve, pinion seal and new pinion nut. If you really want a depth number there is something called a Master Housing Depth (MHD). This value, if you can obtain it is used along with the size of your pinion head to determine the pinion depth. If you want, I might have the master housing value at work. Just know my final decision is always the contact patch so even if I use a depth gauge. If the pattern is off I adjust the depth based on the contact patch. If I remember I will try to find the MHD next week for a 9 1/4" Chrysler and send it to you along with the procedure.
Thanks for the info. i'm resigned to the fact that there is going to be quite a bit of trial & error involved it's just that I'm not used to that sort of thing. I have built many engines & trans & usually have definite specs to work with. That MHD you refer to would be help if things don't go well on the first try. I'm using the original brand bearings so I should be able to get very close on the first try. The pinion depth on the 9 1/4 is set by a shim under the rear bearing (between the bearing & the pinion gear head). I have already pressed the bearing in place so if the gear contact is off I will have to buy a couple more bearings to do the set up. Is there any specified amount of shim to either remove or add based on where the gear contact is located? For example: if the contact is real close to the heel or toe & has to move approx 1/2" to get centered what amount of shim change would get the desired result? There probably is no standard due to the various sizes of the ring & pinion sets but some approx would be helpful. I have made some tools to get the job done. One U tube video showed how to make a carrier bearing adjusting nut tool for the 9 1/4 using a common & cheap hardware store item. I have also made sleeves to press bearings in place. One sleeve is to pull the pinion through the fwd bearing without using the pinion yoke. Frustration w/ the factory shop manual (FSM) is another factor. It says that there are set up markings on the head of the pinion and there are not. Also, the preliminary torque value for the pinion pre load is not accurate. That value is 210" lb & is way too much. Produces over 60" lb drag on the pinion. Again, thanks for taking the time to reply, it's appreciated.
Glad to help. I found the T&D depth tool instructions online. They explain how to calculate pinion depth using the MHD and they also provide the MHD for your 9.25 diff. I have inserted the link below. Unfortunately I have discovered over the years that each diff responds differently to pinion depth .010" shim change. it seems smaller diffs are more sensitive than larger diffs when changing pinion depth shims. If I need to make a change I usually start with a .010" shim change and see how much the pattern moves and adjust from there. Does this diff use a pinion crush sleeve or shims to adjust pinion bearing preload. The reason I ask is because the pinion nut tightening value is not normally given in foot pounds. Normally it's given in rotational force on the bearings. If you have a foot pound specification it might mean that your pinion bearing preload is adjusted using shims between the front bearing and a shoulder on the pinion. If so, you can torque to the 210' lbs and still obtain the correct rotation force just by adjusting preload shims. One last note. If you have a press and a good bearing splitter it is often possible to remove the rear bearing from the head of the pinion without damaging it. Additionally, being a machinist you could manufacture a clam shell tool to pull the bearing off without damaging it.
www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwiY2ej9ntXrAhXmHjQIHa7aC14QFjAAegQIAxAB&url=http%3A%2F%2Ftdmach.com%2Fwp-content%2Fuploads%2F2018%2F01%2FDeluxe-Pinion-Checker-11148.pdf&usg=AOvVaw3d3eEiKFZ0lT4JLCdlFVKH
Thanks great vid