Axle end play problem

[Zip]

Hello,

A few months back, I installed a brand new 8 3/4 diff with Eaton True Trac in my car. Everything fit and worked great, until last week.
I took my rear wheels off to do some brake work, when I noticed the end play in my axles was extremely large (probably like 3/8" or 10 mm). I did install fresh outer (wheel) bearings when I installed the new diff so a little play from their break-in period would be fine, but this seems excessive to me.

At first, I thought the bearings (and their collars) could have started to come loose. I took everything apart, but didn't see that happening. I even threw both shafts+bearings under the hydraulic press to double check. When I didn't see or feel any movement after applying 3 tons of force on them, I realised that wasn't my problem.
So, I thought maybe the end play adjustment was just wrong overall. I put everything back together and tried to adjust the shafts to the right end play. In the end, the adjuster was at the end of its range and I still had 0.030", which is like three times the recommended value.

At this point, I have no idea what the problem could be. The only thing that would make sense in my brain, is the little dowel/thrust pin in the center of the True Trac which "floats" between the axle shafts. Could that have been ground of with driving for some reason? It seems highly unlikely, given that it should be hardened steel and is fully covered in oil, but I just can't think of any other cause to my problem.

I am very curious to what you guys think of this and hopefully some genius out there points me in the right direction! I must have overlooked something.... right?!

Thanks in advance!!

Zip

 

[Big_John]

Is the thrust spacer still in place?

 

[Zip]

Is the thrust spacer still in place?

View attachment 677936

Yes! It is.

 

[volksworld]

if the ends of the axles look fine I'd be pulling the diff to take a good look at the thrust spacer...maybe a junk aftermarket piece that wasn't properly hardened? at this point I don't trust anything new...

 

[Zip]

if the ends of the axles look fine I'd be pulling the diff to take a good look at the thrust spacer...maybe a junk aftermarket piece that wasn't properly hardened? at this point I don't trust anything new...

Yes, that’s what I am thinking too… Do you happen to know the dimensions of it? I might make one myself, just so I know it’s proper quality.

 

[volksworld]

honestly no...never even removed it when I replaced the clutch plates...there are NOS ones on Ebay but i have no clue if the Eaton unit would take the same one as a SureGrip...maybe contact someone like Dr Diff?

 

[Big_John]

I'm not a fan of Green bearings, but this might be one where it could be a good solution. The Green bearings were first used with spools where the center spacer wouldn't stay in place.

I don't think that center spacer is worn out. It may have fallen apart as I have heard of that happening more than once. Probably the place to start is pulling the center section and making sure that it's in one piece.

 

[HOT FURY]

I installed that same eaton truetrac diff in mine and used the green bearings(had no choice due to wilwood brake install requiring them at same time) with about 5000k miles on it now and no issues. Is your end play issue the same on both sides or just one particular side?

 

[Just Carbs]

I'm not a fan of Green bearings, but this might be one where it could be a good solution. The Green bearings were first used with spools where the center spacer wouldn't stay in place.

I don't think that center spacer is worn out. It may have fallen apart as I have heard of that happening more than once. Probably the place to start is pulling the center section and making sure that it's in one piece.

That is something to think about.

 

[MEV]

I have mentioned this before, but do not hesitate to install the green bearings. I am around 10-ish years on mine with a detroit locker and drag radials, plus street driven thousands of miles.

Note: I grenaded a truetrac, before installing the detroit locker, it still never hurt the green bearings.

 

[Zip]

Thanks for all the useful reactions everybody! It sounds like going with the Green bearings will be the easiest solution.
I did speak to Dr. Diff for a bit, and they told me that the tolerances in 8 3/4 True-Tracs are usually pretty sloppy. You really can't trust any manufacturer to deliver good quality parts anymore I guess...
Anyways, thanks guys!

 

[jmustian]

Does anyone know where to get a right Axle end play adjuster?
My axle was making noise and I changed all the bearings. I adjusted the right axle and the adjuster out almost all the way. Put the lock on it and 50 miles later the lock was bent and the adjuster had turned itself off. It appears the adjuster is worn out and the adjuster tips are so burnt up they keep grabbing the axle. The inner tangs are so worn they are riding on the outside of the axle just like the outer tangs.
OR is this the time to go with green bearings and do green bearings eliminate the adjuster?