8 1/4 axle inspection.

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A further thought from the cosmo.

A lot of times on the back end of an aftermarket pinion there will be a number etched in it. It'll be something like 4.5 or 4.73 or 3.2 anyway that number is the measurement from the back of the pinion to the center line of the carrier.
So you place a pushrod or ruler angled across the housing under the caps. Then measure the distance from the back of the pinion to the underneath side of the pushrod or ruler whichever you're using and if that number is equal to the number etched on the back of the pinion then you're good.

However if your number is smaller than what is called for you would remove shims from behind the inner pinion bearing.
Just the opposite if the number is bigger you would add shims behind the inner pinion bearing.

If you go to put a new set of gears in this I highly recommend that you use the same thickness of shims as the original pinion used for starters.
 
Some days just don't go well. After a terrible day at work I went up to shop to put everything together. I picked up a new crush sleeve. Before I put thinner shims in I had the pinion preload at 25 inch pounds with no problems. Now I can not get any preload. I have the nut way tight and there is no preload. I actually stripped out the old nut. Without sleeve I can get preload. I had a good gear pattern with proper backlash, but did not have the crush sleeve in or seal. I took the pinion and crush sleeve down to a shop that is real helpful. On the way the pinion rolled around and all the rollers came out of cage. So another new bearing and I called it a day. I wish I would of got the crush sleeve eliminator.

One question I have. is there suppose to be a slinger between the bearing and pinion? There was not one on disassembly. I will try again tomorrow. Thanks for all the advice.
 
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swifty said:
Some days just don't go well. After a terrible day at work I went up to shop to put everything together. I picked up a new crush sleeve. Before I put thinner shims in I had the pinion preload at 25 inch pounds with no problems. Now I can not get any preload. I have the nut way tight and there is no preload. I actually stripped out the old nut. Without sleeve I can get preload. I had a good gear pattern with proper backlash, but did not have the crush sleeve in or seal. I took the pinion and crush sleeve down to a shop that is real helpful. On the way the pinion rolled around and all the rollers came out of cage. So another new bearing and I called it a day. I wish I would of got the crush sleeve eliminator.

One question I have. is there suppose to be a slinger between the bearing and pinion? There was not one on disassembly. I will try again tomorrow. Thanks for all the advice.
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if i am reading this right ,, after you installed the -- new crush sleeve -- you have no preload -- you will not have any preload until you actually crush the sleeve this can take up to 400-500 ft/lbs of torque on the nut --- and with new bearings the preload should be in the 20-30 inch/ pounds range rotating .
not crushing the sleeve properly is one of the biggest mistakes made-- this cannot be done with a 2 foot breaker bar you will only tighten the nut down to the sleeve-- not any where near crushing it -- i use a 40 inch 3/4 drive bar to set pinion preload and with both hands on it and pulling with all the strength i have to set the pinion bearing preload.
 
Yeah I am not getting a crush. I am using a lot of torque. I stripped out the original nut and the threads are not the best. Would it help to heat sleeve to crush easier? I was told by someone they have used a press to get crush started. Then install and finish crushing.
 
DO NOT heat the crush sleeve --- for salisbury type differentials ( 8-1/4 mopar , 8.8 ford and 10 & 12 bolt chev etc. ) i have built a bar that fits on/over the yoke to hold it steady --- the housing is placed on the floor with the yoke tool installed then i proceed to tighten the pinion nut with that 40 inch breaker bar , checking the preload as i slowly tighten the nut.
 
Ok here is where I am at. Axle is together less oil and drive shaft. I needed to make it a roller. The gear mesh and backlash are good. The problem is the pinion preload. The threads on pinion are so bad I can not get it tight enough. The nut is extremely tight but not crushing sleeve. I have stripped out 2 nuts already. There is some preload but not the spec. There is more preload than when I started.

So I had the idea of trying a thread chaser to clean up threads. If I measure preload with brake hubs off, remove nut and pinion. Chase threads and reassemble. If I can get it tighter and add 20 inch lbs would that put me in the ballpark? I know I should get a new ring and pinion but I am trying to get by for now for an 8.75 swap.
 
swifty said:
Ok here is where I am at. Axle is together less oil and drive shaft. I needed to make it a roller. The gear mesh and backlash are good. The problem is the pinion preload. The threads on pinion are so bad I can not get it tight enough. The nut is extremely tight but not crushing sleeve. I have stripped out 2 nuts already. There is some preload but not the spec. There is more preload than when I started.

So I had the idea of trying a thread chaser to clean up threads. If I measure preload with brake hubs off, remove nut and pinion. Chase threads and reassemble. If I can get it tighter and add 20 inch lbs would that put me in the ballpark? I know I should get a new ring and pinion but I am trying to get by for now for an 8.75 swap.
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how did the threads get so boogered?
 
swifty said:
Ok here is where I am at. Axle is together less oil and drive shaft. I needed to make it a roller. The gear mesh and backlash are good. The problem is the pinion preload. The threads on pinion are so bad I can not get it tight enough. The nut is extremely tight but not crushing sleeve. I have stripped out 2 nuts already. There is some preload but not the spec. There is more preload than when I started.

So I had the idea of trying a thread chaser to clean up threads. If I measure preload with brake hubs off, remove nut and pinion. Chase threads and reassemble. If I can get it tighter and add 20 inch lbs would that put me in the ballpark? I know I should get a new ring and pinion but I am trying to get by for now for an 8.75 swap.
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You need to stop an take a deep breath.
Get a crush sleave Eliminator.
Then set the pinion preload.
Then remove the nut put on some loc tite and it torque down.
 
rustycowll69 said:
how did the threads get so boogered?
Click to expand...

Mostly from taking nut on and off. That nut is soft and when we tried to crush the sleeve with 4' wrench the threads gave out. The ends threads are the worse from were the locking part of nut drags over. Should of picked up a none locking nut for setup.
 
Old pinion, i mark the nut and the shaft, install new bearings and seal then re-assemble with old crush sleeve. Line the marks i made previously and check preload. I can increase preload but not decrease.
9/10 times it goes together without issue. This applies to every diff i ever put a pinion seal in without issue. And of course locktite the nut.
 
if you can't find a die or die nut to chase the threads, maybe you can find a thread file to dress the threads. I don't know if you have seen one, but they are about 8 -10in long, square shaped in cross section, and each end has four flats with different pitch sharp " "v" "threads" to properly dress mildly-booger ed threads. Just figure out what is the correct pitch, and whether it's SAE or metric. They cost maybe $10 each.
 
Like suggested gonna go over options. Weather here is turning to winter so I have some time. I found a die I can borrow so I can try cleaning up threads. Not sure if I should try crushing sleeve or start over with sleeve eliminator. I do know if I could hit rewind, I would start with the eliminator and use a regular nut for setup. Bad thing is car is home now so I don't have a lift. It drove fine, way less whine, but I took it real easy because of worried about pinion. Thanks for all the help.
 
swifty said:
Like suggested gonna go over options. Weather here is turning to winter so I have some time. I found a die I can borrow so I can try cleaning up threads. Not sure if I should try crushing sleeve or start over with sleeve eliminator. I do know if I could hit rewind, I would start with the eliminator and use a regular nut for setup. Bad thing is car is home now so I don't have a lift. It drove fine, way less whine, but I took it real easy because of worried about pinion. Thanks for all the help.
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If you drove it without rhe proper pinion setup you probably have already damaged the gears. It does not take very far.
If you use the eliminator you are not using great amounts of force to crush it. Therefor no stripping of threads.
 
It can be but you won't be doing it right. And probably would never get the preload righr.
Why don't you want to do it correctly?
 
Jadaharabi said:
It can be but you won't be doing it right. And probably would never get the preload righr.
Why don't you want to do it correctly?
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Because I don't have car on lift anymore. So will be doing on jack stands. Just wondering if there is a way of doing without pulling carrier. If I have to pull carrier I may change ring and pinion.

My thought are that I will pull yoke, pull seal. Try to clean up thread with die. If I can get it decent, install crush sleeve eliminator and set preload. If I have to pull carrier I will. Just wondering if there is a way not to. If threads will not clean up. New ring and pinion or wait for 8 3/4.
 
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Have not been on for a while but thought I would finish what I started. I picked up a Yukon gear set on ebay cheap. I did not have access to a lift so I took it to a shop near me. The owner helped me out numerous times so I figured I would give him the business. He installed the gear set for about $400. He also put the shim kit in instead of the crush sleeve. Nice and quiet. Money well spent.

Car drove better but still had a bad vibration above 55. Took drive shaft to a local place and they replaced u-joints and the front slip yoke. They also balanced it. The crush sleeve eliminator came in handy when reassembling. It is like driving a new car. So if you have a bad vibration when decelerating check the slip yoke and output shaft bushing. So car drives great now, is quiet and even seems snappier.
 
Glad to hear it.


steering.gif
 
I hate seein long drawn out problems like this. Glad you got it sorted out so you can have some fun!
 
Just reading through this thread for my gear change and plenty of good info given. Would like to add 2 things.
As far as axle wear goes as previously mentioned, there is a bearing fix out there that moves the bearing onto a different
part of the axle. IIRC was mentioned in an article I read and R.A. Has them. I'm sure others do too.
Secondly is that a C body torsion bar end is the same size as the side carrier adjuster and long enough to fit
in the axle tube.
This applies to 9.25 rear also.
 
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