Rear end's posi is over..

[AKIRA]

A pinion bearing is pretty much gone in my rear end and my "clutch pack" is no longer giving me posi traction. This is all German to me. The only thing I know about a rear end is what gear ratio to get and maybe which rear end cover to keep the 10-bolt as strong as it can.

The mechanic said the cheapest route would be to get new "clutch packs." I asked if the gears couldve been screwed up from the pinion bearing and he said he wouldnt know until he opened it up. He explained how he knew it was a pinion bearing that was screwed cuz the car makes a noise the second it takes off, in other words, this is a diagnosis without going in there.

BUT!

Since I am going in, I am worried that other things might be messed up and theres no point in paying for an installation twice (seeing as how I cant be without the car for a long period of time), I was thinking of what to do...

After a recent thread I figured I had an Auburn rear(?) and I didnt know if I could just replace these clutch packs (where the fuck can I get these????) or if I should get an Eaton or a Torsen. Again, this is all new to me.

I need some reccomendations here. I dont race the car too much anymore. I havent been to the track in over a year.

[9t8z28]

Is the pinion seal leaking?
As far as wether to keep the Auburn, I don't know. I bought my car when the clutch packs were allready gone. So I don't know the reliability of that setup.
With the pinion being loose, sometimes you could just retorque or reset the tolerances if you wanted to make it last longer. I have done this to many 4 wheel drive vehicles and in some cases, iy stopped howling!
If it helps at all: I have a torsen setup with 135,000 miles of hard driving!! Never had a problem with it!!!!!

[AKIRA]

Apparently there are no leaks. FIRST TIME EVER. The "clutch packs" lasted until I guess 90k?

[Wesman]

I'd invest in an Eaton Powertrax locker. Its got the benefits of a fully locking diff, without the ratcheting and squealing around turns that lockers tend to have. Both wheels spin, unlike the torsen, that "senses torque" and tries to distribute power to the wheel with more traction.

It can also be installed without removing or altering the ring and pinion, so you could even do it yourself. However, if your pinion bearings are shot, you will have to get that addressed by a mechanic separately.

[01Z28M6]

To my knowledge your 99 TransAm has a Zexel Torsen from the factory unless it has been changed out. It has no clutches in the differential so it can't be rebuilt in that regard. Your mechanic should know that so take care as you allow him to start work on your car.

[Dillard99]

hey check out this web site at www.thirdgen.org/beefinguprear
this guy gives you step by step on how to beef up your 10bolt
good info I will be starting my step up soon.

[AKIRA]

To my knowledge your 99 TransAm has a Zexel Torsen from the factory unless it has been changed out. It has no clutches in the differential so it can't be rebuilt in that regard. Your mechanic should know that so take care as you allow him to start work on your car.

He installed the 373s a couple of years ago, so Id say he rememebers what was in there.

In any case, where are these "clutch packs" to buy anyway? Ive never heard of them.

[volleybill]

Eatons have clutches, Auburns have cone clutches, Torsens don't- You can get new Eaton clutches, I don't think the factory Auburn stuff is re-buildable. If you went Eaton, you can change the spring bias on the Eaton, make the pressure locking the clutch plates together higher.

AFAIK, you have a torsen, which is a load-sensing diff- the wheels may spin easily on the lift, but they should lock together under a good torque load. Have you done a couple burn-outs to see if it is is working?

[AKIRA]

No I havent burned out in a long time. Years. And I beleive he said I had cone clutches...

Doesnt seem to be a cheap way around this one huh? My mechanic explained to me about all this stuff, though it was too technical for my full understanding, he did say that products like a Detroit Locker could be dangerous the rain if the tires cut loose.

[9t8z28]

Eatons have clutches, Auburns have cone clutches, Torsens don't- You can get new Eaton clutches, I don't think the factory Auburn stuff is re-buildable. If you went Eaton, you can change the spring bias on the Eaton, make the pressure locking the clutch plates together higher.

AFAIK, you have a torsen, which is a load-sensing diff- the wheels may spin easily on the lift, but they should lock together under a good torque load. Have you done a couple burn-outs to see if it is is working?

Factory Auburn's are rebuildable!

[01Z28M6]

Factory Auburn's are rebuildable!

http://www.auburngear.com/aftermarket/drex/

[9t8z28]

http://www.auburngear.com/aftermarket/drex/

Nice work! I didn't realize that. Why the hell would they not make it rebuildable? $100 ain't bad!
How long have you guys had these things last?

[AKIRA]

Ok so to go to an Eaton...what is everything that I would need? Looking at a Summit catalog for example, what would I get to make this job over and done with?

[AKIRA]

http://www.auburngear.com/aftermarket/drex/

Or could I just buy this? I didnt know if I should buy an installation kit or SOMETHING else to complete the job.

[01Z28M6]

The D-Rex offer is pretty time limited. I think 3 years or maybe 5. I know mine was way past the replacement limit so I bought one out of a 2000 Z28 with just a few thousand miles on it for $75. If you want to save money that is one way to go.

I'm pretty certain you have a 3 series carrier (differential) because of your 3.73 gears. There is a chance that you have a 2 series carrier with special thickness ring gear or a spacer. But if you do have the expected 3 series then all you will need is a new or good used 3 series differential, 10 new bolts, a new gasket for the gear cover or just use ATV and some loctite if you want to use it on the new bolts. All your side shims should work if you don't mix them up when you pull the bearing caps off but then again a different carrier might change things. Mine didn't and I went from an Auburn to a Zexel.

Those are the parts you will need but if you are going to do the work yourself, all you need is basic hand tools a torque wrench AND an indicator to check for proper lash and that the ring gear is running within a few thousandths concentric. It's only a check because you aren't changing pinion depth and using the same ring gear. These 1 inch travel indicators with a magnetic base can be bought for under $30.

[volleybill]

Don't forget the pinion bearing, the reason you are going in there in the first place- actually, if you are going in with new parts, and going to go through the trouble of installing new parts, it would be a good idea to do all the bearings- for a few bucks more in parts, no more in labor or time, have all new moving parts. If the pinion bearing wore out, how much life is left in the other bearings?
DOn't forget a mild break in for a few hundred miles, heat cycling a few things- then change the fluid. And use the limit slip additive in there, or run synthetic gear oil- BTDT

[AKIRA]

Can these be bought in a kit? Say a Ratech installation kit?

[AKIRA]

Ok heres an update..and if I fucked up I guess let me know.

I went ahead and purchased an Eaton Posi Performance differential from Summit ETN-19599-010

And a Ratech Install Kit
RAT-308TK.

I hope this will all fit.. What do you guys say?

[Wesman]

Ok heres an update..and if I fucked up I guess let me know.

I went ahead and purchased an Eaton Posi Performance differential from Summit ETN-19599-010

And a Ratech Install Kit
RAT-308TK.

I hope this will all fit.. What do you guys say?

As long as its for a GM 7.5 inch 10 bolt, then it should work fine.

Eaton makes good differentials, so don't worry about it

[AKIRA]

As long as its for a GM 7.5 inch 10 bolt, then it should work fine.

Eaton makes good differentials, so don't worry about it

Goodie!

I wonder if Ill notice a difference in drivability..? It would be nice to not hear that fucking howling anymore!