Eaton Truetrac

**pajeff02** · 12-19-2009, 03:17 PM

Picked up my Moser 12 bolt from the speed shop on Thursday. After we got it home, I unpacked everything to check it out. Wanted to make sure the axle splines matched the innards, but when I slid them in they stopped just under an inch short of where they need to be.

It appears that the posi unit has the c-clip spacer installed even though the axles I ordered are retained by the backer plates. The directions are not very clear, so I assume I simply have to remove the spacer. Do I reinstall the plug in the side of the posi after removal, or just leave it out as well? Or, is there any chance that this is not the correct unit for my axles? The only reason I ask is that the instructions seem to suggest specific setups for c-clip versus non-c-clip retained axles.

I checked the Moser website and could not find any information on this. Their "Moser Forum" is apparently down for maintenance. The instructions are linked here: http://www.eaton.com/ecm/groups/publ.../ct_128482.pdf

**pajeff02** · 12-20-2009, 05:25 PM

Here are some pics of the setup. The red circle in the shot down the axle tube shows what I think is the c-clip spacer. I'm not sure, maybe it is simply the bottom of the access plate. The other pic is of the access plate in the side of the posi unit. The axles definitely hit on this before reaching the point they would need to be inserted for the bearing to be fully seated in the end of the tube.

**GTP231** · 12-21-2009, 12:55 PM

Sure you have the axle lined up right so it'll slide into the diff itself? I'd be on the phone with Moser trying to get some answers. I'm assuming you're looking down the diff in the 1st photo?

**Zapper2003** · 12-21-2009, 12:58 PM

Jeff, thats the exact same diff that I put in my car. It looks to me like they mighta shafted you a bit here. That piece in the center, the round disc, is very hard to install once the gear is in place as its machined very tight and dropping it straight in is nearly impossible because of the tips of the gear teeth. Regardless, it does fit. It's tapped 1/4" in the center to attach a bolt to pull it out, it does not fit tight. If I can find my install instructions, I'll take a peek and see what it says about non clipped axles. Mind you, mine is still a 10 Bolt with c's, but I can't imagine the design to be much different.

**pajeff02** · 12-21-2009, 12:58 PM

Originally Posted by GTP231

Sure you have the axle lined up right so it'll slide into the diff itself? I'd be on the phone with Moser trying to get some answers. I'm assuming you're looking down the diff in the 1st photo?

Axles slide right in and engage the splines -- but then stop when they get to what I beleive is either the access plug or c-clip spacer. First photo is looking down the axle tube -- you can see the protrusion that the axles hit on. They are stopping about 1/2" - 3/4" from where they need to be.

**Zapper2003** · 12-21-2009, 01:02 PM

Alright Jeff. Just re-read your first post. All they have installed in your car is the retainer plate for the c-clip axle spacer. If you can see directly straight through your diff, the spacer isn't installed, only the retaining plate. I have a picture to upload shortly for your viewing pleasure.

**Zapper2003** · 12-21-2009, 01:13 PM

Okay, here's the pictures. As for what to do to install your current axles, Jeff, you'll probably have to make a phone call to Eaton and ask their tech department. My instructions do not tell me how to handle this situation, however, I don't think the retaining cylinder is necessary for correct operation. My only worry would be balancing (no retaining cylinder offsets the weight of the diff a bit), however, it could be so close to the center of movement that it would not matter much (similar to a brake rotor being off balance vs. the tire).

**pajeff02** · 12-21-2009, 01:16 PM

Originally Posted by Zapper2003

Jeff, thats the exact same diff that I put in my car. It looks to me like they mighta shafted you a bit here. That piece in the center, the round disc, is very hard to install once the gear is in place as its machined very tight and dropping it straight in is nearly impossible because of the tips of the gear teeth. Regardless, it does fit. It's tapped 1/4" in the center to attach a bolt to pull it out, it does not fit tight. If I can find my install instructions, I'll take a peek and see what it says about non clipped axles. Mind you, mine is still a 10 Bolt with c's, but I can't imagine the design to be much different.

I'm certainly stumped -- I'm heading home in a few and will pick this up again from there.

Originally Posted by Zapper2003

Alright Jeff. Just re-read your first post. All they have installed in your car is the retainer plate for the c-clip axle spacer. If you can see directly straight through your diff, the spacer isn't installed, only the retaining plate. I have a picture to upload shortly for your viewing pleasure.

Cool. Let me know if you need a pic of anything else on it.

**pajeff02** · 12-21-2009, 01:17 PM

Originally Posted by Zapper2003

That helps -- so it's just the retainer and no spacer. The instructions are so damn vague I figured that they were written by a lawyer!

**Zapper2003** · 12-21-2009, 01:25 PM

Yes, the instructions really offered NO advice for me whatsoever, it doesn't even show this design!

Assuming you're familiar with the c-clip axles, if you previously had this rearend installed in the car what you'd have to do in order to pull the axles would be to pop off the snap ring, then pull out the retainer, and lastly get the spacer our via magnet or rotating the diff down and dropping it out, then pushing the axles IN to disengage the c-clips from their grooves, then remove them from the axles via magnet or dropping them off as well, then you pull the axle. The way I see it, if you took all of these parts out and had your backing plate retained axles installed, there's no need or reason for any of those parts to be put back in.

Like I said though, call Moser first and make sure they didn't mess up and sell you the wrong diff, secondly, call Eaton and make 100% sure that it IS the correct unit for your application and make sure that not reinstalling the spacer/retainer isn't gonna screw anything up. The spacer was only in there to separate the axles and keep the clips in their grooves in the side gears, and the only reason the retainer is in there is to keep the spacer in its place. Mine all came shipped loose and nothing fell out of the diff, so I really don't see how not having them in could be any kind of problem.

**pajeff02** · 12-21-2009, 02:43 PM

I am going to head back out in the garage and look it all over again. I sent an e-mail off to Moser on Saturday, but no reply as of yet. I have some time tomorrow and will try to get a call out to them. If you get down our way after the holiday stop in and check it out.

**Zapper2003** · 12-21-2009, 02:47 PM

Yeah if I get down that way (weather pending of course) I'll see what I can do.

**pajeff02** · 12-21-2009, 05:12 PM

Wow. I can be amazingly dumb at times.

Went back out into the garage to take another gander. Measured the axles, looked things over again, and then decided to check the bearings. Turns out I was looking at the wrong step on the axle. Having rear disc brakes, I figured the bearing would seat against the outermost step. It doesn't. The bearing seats against the first step, which means that everything is just fine.

Here's the bearing next to the axle:

This shows the steps as the axle is slid into the housing:

And this is where the axle will ride when the bearing is pressed on:

I have no idea what the hell I was thinking.

**Zapper2003** · 12-22-2009, 12:56 PM

, so there's nothing wrong with the diff, you just need to get the bearings pressed onto the axle shafts?

**pajeff02** · 12-22-2009, 01:07 PM

I need to swap over the backer plates from the existing axle before I press the bearing and lock ring on. What's funny is that my friend also looked at it and thought the same thing I did. It's been a few too many years since I have had to swap out an axle bearing, that's all I can say.