LOL It is not a wheel bearing problem, there is NO support at the spline end of the axle with this type of carrier, the side gear will move around & lets the axle move.

Use the thrust block supplied with the unit. Use tapered roller bearings, adjust them properly with .08" of clearance and all will be good. As for the original question as to what is a good alternative differential you could get the cone type and it would perform well on the street.

You are correct, there is nothing holding the axle in the center section, that wheel movement you see is the axle pivoting at the wheel bearing, the end float in that clip is set at 0.004" with a DTI, the bearing is tight in the housing, I am holding the wheel at 3 and 9, pushing with one hand pulling with the other, (just like you do on the front wheels to check for loose bearings).I can tighten the adjuster on the wheel bearing to no end float and still wobble the wheel. Futher to this, I swapped centers back to the factory open center (single spinner)used the same axles, same bearings, same set up only now Im using 0.008" axle end float, (ONLY THING I HAVE CHANGED IS THE DIFF CENTER, WHICH THE SIDE GEARS HAVE NO MOVEMENT GO STICK YOUR FINGER IN ONE IF YOU HAVE ONE LAYING AROUND) guess what,,,,,,,, noise is gone so those suggesting its the wheel bearing, think again.

What exactly is Eaton telling you is in spec ??? And they diagnose this over the phone ??? Can you slip an axle in the 3rd member{out of the car} and see exactly what's loose and how it can be corrected ??? Sounds like there's a quality control issue that needs addressed the trouble is getting the company to admit it..

Screamin, Cass has been talking to Eaton on this, he has multiple video's showing the side movement and agree's there is a problem, he spoke to them at SEMA and all they are saying is, its in spec, regarding the side gear movement, Cass is still arguing this with Eaton, when I first raised it with Cass, about 12-18 months after I purchased it, and about 2000Miles on it, I had been chasing the rattle from new, thinking it was exhaust, tailshaft, on and on you name it, then one day I just grabbed the wheel and wobbled it to find out it was as indicated, I knew the axle spine fitted well, figured I best just pull the third member for now and woek on the noise, now, at that point I reached out to Cass, I didnt buy it directly from him, a mate did, anyway Cass is an awesome guy as well all know, Eaton sent out a new replacement at no charge, again I praise them for this service as technically it was out of warranty, both Cass and Eaton went above and beyond, something rare in my country. Yes I can poke an axle into the bare Trutrac center and it will move side to side,,, lots. When compared to mopar single spinners or cone/clutch, their side gears have no movement. Im at a lose for now, I will pull one of them apart to see if there is a reason why they are like that, maybe they need to be that loose for whatever reason, the other thing is I have a 0 offset on my wheels maybe if I had more wheel out (less backspace) thus loading the axle more it would make no noise, who knows,

100%... I got my 9" center (with trutrac) and axles from Cass.

(For the 9" diff in my Torana )


Sure is a shame though with all the issues on your's..

After overnight comms with Cass, looks like I will be trying to find a Dana housing out here as a donor to build. He has confirmed that there is no side gear movement on Dana or Strange build TruTrac's, probably the same with 9", so it seems only the 8.75" have an issue.

Since that axle gear meshes with the two spyder gears, there has to be some way this gear is "controlled" by design. On stock set ups the axle gear fits into a precision recess. This has to be similar to the unit you have, except parts or something is missing. Without this control the spyder gears would have incorrect mesh/lash.

I can't imagine someone would design that gear to flop around like that as the mesh with the spyder gears and the thrusting apart of these gears is what applies the force to lock the carrier up either with clutches or cone or whatever.

If you take it apart please let us know what you find. Best of luck to you.

I know SportF, seems crazy to me, thats why I'm at a loss with this, I'll pull one of them down and have a look and let you all know, right now I'm looking for a Dana or 9" PITA having to cut them down and mod them when the 8.75 was a nice drop in afair. But, thats what you get when you play with cars right??

Why are you still hung up on using a TruTrac? You have a good 8-3/4 with the exception of the diff unit, why not keep everything and go with a new/different diff unit? It would be a lot less hassle and expense than finding and building a Dana or 9" !!

Stanton, good question! Pretty much what I asked in my first post, I guess my options are, Detroit locker, cone style, clutch pack style and spool, are there any others to throw in the mix? When I track it, it will have slicks and I'm pushing for around 500 RWHP, we should hit 600 flywheel easily. 727 and not a transbrake.

I'll offer that my experience with the Detroit locker has been just fine. Been running one in my 8.75 for 3 years now. People say they are noisy; I rarely hear a thing. People say they clunk in & out... I occasionally feel it "shift" or "unlock" when slowing while going around a corner, but as long as you know what it is... no big deal. Durability wise: its been bombproof. The only issue I have with it is that as you get on and off the gas, it will want to push the car left or right as it unlocks and locks. This is no big deal, until you chop the throttle a couple of times at the top end of the drag strip at 115 mph. Then, it will get your attention. As I look to do more racing over the next few years, I will likely be going to a spool partly because of that issue. If it weren't for the racing thing, I'd be happy as a could be with my locker.

As someone whos logged at least 100000 miles in detroit equippped trucks, I love em.

Spendy but bulletproof and always there since there's not really anything to wear out like clutches.

Thanks guys, thats what I'm leaning towards right now, unless I can find a Dana 60 out here from a F250 or similar, we dont have Dodge vans or light trucks so they are thin on the planet here.

If you have that much power, and slicks, you should cross ANY type of CONE type off your list or you'll be back in it again , CONE types are GARBAGE by design .

I agree as I have been running a Detroit Locker in my 8-3/4 about 6 years. But I have never had any problems of it making my car go to one side or the other. After I go through the traps I just lift the throttle and it slows down straight as an arrow even when braking or downshifting.