TrueTrac Axle Endplay

**Wesman** · 03-16-2011, 02:21 PM

Just rebuilt the entire rear end of my car a couple months ago, its a factory 7.5" 10 bolt. The original Auburn diff exploded so I replaced everything.

New parts included Motive 3.42 gears, Detroit TrueTrac diff, Moser axles, new c-clips, all new Timken bearings, and new seals.

The problem is there is excessive endplay in the axles, meaning there is too much clearance between the inner end of the axle shaft and the "spacer" inside the diff. So every time I come around a turn hard, the axles slide inward or outward, and often cause pad knockback.

Anyone else running a TrueTrac diff and having this problem??

The only solution I can think of is to have a machine shop make a new spacer that is wider so it takes up the excessive clearance between the two axles. They don't come in far enough for the c-clips to come out, but its enough to cause pad knockback and noise.

**Demon_Z28** · 03-16-2011, 03:45 PM

That's weird. You can't shim the axles or use thicker C-Clips?

**Wesman** · 03-16-2011, 04:09 PM

Originally Posted by Demon_Z28

That's weird. You can't shim the axles or use thicker C-Clips?

Thicker c-clips would work - they would effectively push the alxes inward closer to the diff spacer, taking up some of the clearance.

The problem is, where would I find thicker c-clips??

**Demon_Z28** · 03-16-2011, 05:23 PM

Not sure... maybe moser has them if they made your axles.

**pajeff02** · 03-16-2011, 05:25 PM

Did you compare the Moser axle length with your stock axles?

**Wesman** · 03-16-2011, 05:44 PM

Originally Posted by pajeff02

Did you compare the Moser axle length with your stock axles?

Yes sir...same length.

Also note that this was a pre-existing issue before the diff blew up.

I attributed it to worn side gear clutches in the diff allowing excessive clearance - so I figured new diff, axles, and c-clips would correct the issue.

No such luck...

**pajeff02** · 03-16-2011, 05:52 PM

Originally Posted by Wesman

Yes sir...same length.

Also note that this was a pre-existing issue before the diff blew up.

I attributed it to worn side gear clutches in the diff allowing excessive clearance - so I figured new diff, axles, and c-clips would correct the issue.

No such luck...

Interesting. I have a True Trac and Moser axles but no c-clips, so I can not comment. Any chance your spacer is worn?

**Wesman** · 03-16-2011, 05:54 PM

Originally Posted by pajeff02

Interesting. I have a True Trac and Moser axles but no c-clips, so I can not comment. Any chance your spacer is worn?

Nah the spacer still looks brand new, the diff only has about 500 miles on it.

This is driving me crazy...

**pajeff02** · 03-16-2011, 05:58 PM

Originally Posted by Wesman

Nah the spacer still looks brand new, the diff only has about 500 miles on it.

This is driving me crazy...

Maybe Cutlass or FBJ might have some ideas on this one.

**Wesman** · 03-16-2011, 06:09 PM

Originally Posted by pajeff02

Maybe Cutlass or FBJ might have some ideas on this one.

Yea they know their stuff.

The issue really has to be within the diff...regardless of axle length, ect.

The bottom line is that the center spacer is supposed to prevent the axles from moving inwards, while the c-clips are supposed to prevent the axles from moving outwards. The tolerance between all this should be very tight, not 1/4"-1/2" on each side lol!!

So either my c-clips are too thin (they are OEM size) or the spacer is too narrow.

Why this has happened, that is the puzzle I suppose.

**Knight** · 03-16-2011, 06:16 PM

I have the same setup as you, but I don't know the dimensions of the clips or the spacer off hand. I would suspect, as you have, that either the clips or the spacer is the wrong size.

**Cutlass** · 03-16-2011, 06:20 PM

Since it is a problem before and after, I'd guess the C-clips are worn out. Although I'll admit, I've never seen or heard of that. But they should be cheap enough to guess at. Either that or get a c-clip eliminators.

**Demon_Z28** · 03-16-2011, 08:42 PM

Can you get C-Clip eliminators on a 10 bolt?

**Wesman** · 03-17-2011, 08:53 PM

Originally Posted by Cutlass

Since it is a problem before and after, I'd guess the C-clips are worn out. Although I'll admit, I've never seen or heard of that. But they should be cheap enough to guess at. Either that or get a c-clip eliminators.

I actually bought new c-clips already hoping that would fix the problem, same issue!!

After searching the internet, it looks like I'm not the only one with this problem. Apparently Moser axles have larger c-clip grooves than stock axles (didn't notice a visual difference when I installed them) and can cause excessive endplay.

One guy from 3rdgen.org went through many attemps to try and find a solution, and he ended up using external snap rings as spacer. Basically he put the snap rings on the c-clip groove and then inserted the c-clip next to them, with the snap rings closest to the end of the axle. The snap rings effectively take up the slack between the c-clip and its groove, allowing it to fit tightly between the side gear and diff spacer. Snap rings are made of "spring steel", and he reported that after extensive use they showed no signs or wear or fatigue. Looks like this may be the next thing I try to fix the problem.

As for c-clip eliminators, as much as I'd like to run them, I can't find a "street" version for the 7.5". They are all "drag race" versions, which means they are ball bearings instead of roller bearings and cannot be subjected to the side loading that the car would see on the street or road course. They make a tapered roller street setup for the 8.5" 10 bolt, but nothing for the 7.5"!! Too bad, that would be a nice solution!!

**pajeff02** · 03-18-2011, 03:17 AM

No reason the snap ring should not work and last the life of the axle. Certainly do not hear many good things about Moser on here.

**LS ARKY** · 04-07-2011, 05:48 PM

Just finishing up a 67 ss ragtop camaro with a 10 bolt 8.5" truetrac setup, 2001 LS brakes all the way around, Wilwood 7/8" bore manual brake setup.

I am having the same problem with excessive endplay.

Have stock axles with tight c-clips.

Without the cross pin any endplay is doubled because the axles are pushing against a floating spacer instead of the fixed pin.

This is causing excessive pad knockback which eats up most of the first brake pedal stroke after a hard s-curve.

Has anyone come up with a solution for this???

Thanks

**LS ARKY** · 04-07-2011, 06:29 PM

Just read a post on a jeep forum where an Eaton rep suggested welding up the axle ends and machining them to take up the excessive play???????????

**pajeff02** · 04-07-2011, 06:30 PM

Originally Posted by LS ARKY

Just read a post on a jeep forum where an Eaton rep suggested welding up the axle ends and machining them to take up the excessive play???????????

I assume the axles are heat treated. Probably not a wise idea.

**Smittro** · 04-08-2011, 12:52 AM

Originally Posted by pajeff02

I assume the axles are heat treated. Probably not a wise idea.

Agree, likely rip the splines right off the axle...

Or worse.. Have the end twist off, and the axle walk out of the housing..

**Smittro** · 04-08-2011, 12:58 AM

Originally Posted by LS ARKY

Just finishing up a 67 ss ragtop camaro with a 10 bolt 8.5" truetrac setup, 2001 LS brakes all the way around, Wilwood 7/8" bore manual brake setup.

I am having the same problem with excessive endplay.

Have stock axles with tight c-clips.

Without the cross pin any endplay is doubled because the axles are pushing against a floating spacer instead of the fixed pin.

This is causing excessive pad knockback which eats up most of the first brake pedal stroke after a hard s-curve.

Has anyone come up with a solution for this???

Thanks

What are "2001 LS brakes"?

If you mean 4th gen f-body brakes excessive brake peddle can also be frozen calipar pins..

To the OP,
I also agree there seems to be a constant issue with Moser axles specifically..