Found a guy selling 2 rear ends from '98 ls1 cars. The stock one doesn't include brakes and is from an auto car. The other has an aftermarket diff cover and is supposed to be 343 gears. I'll be driving a hour and a half to get them but I will pull the cover to get a better look. Both for $175. I just wanted to make sure they are 4 th gen fbody rears before I waste my time and money.

-thanks

 

Looks like it to me. I don't recall any 3rd gens having the speed sensor on top of the housing.

 

What all should I look for? Is it pretty simple as far as looking at the gears once the diff cover is off? Metal shaving or messed up gears?

 

175 for both I wouldnt concern myself with the shape of the gears just rebuilt the one your gonna use before you put it in your car. Most of the f-bodys being parted have 100000 plus miles

 

If the one does need to be rebuilt how much am I looking at? These years are rebuildable and have the better zexel posi? I don't know much about tears-still reading up on the 4th gen swaps.

 

Be sure that they don't have the Auburn. If they have the Torsen then they are worth it.

 

How can I tell the difference?

 

I'm pretty sure the torsen did not get installed until 99.
I had a 98 with a clutch type posi in it. My 2000 TA had the torsen.

 

If you look inside the differential and you see 5 coil springs then it's the Auburn.

 

I asked the seller to remove the diff cover and take a pic but he said he'd have to unbolt all the preloads? Is this true or can't you just unbolt the actual diff cover?

 

He is talking about the preload bolts in the TA Performance cover. It's no big deal to do it, he just doesn't what to mess with it.

 

Can I just unbolt it all to inspect the gears?

 

Yes, but the preload will have to be set again. It's an easy thing to do, but requires a small torque wrench and thread sealer.

 

Well after a 4 hour drive round trip later I've got both rear ends in the bed of my truck. Snapped a few pics-both have the "TA" diff covers. One is supposed to be 2:73 gears and the other a 3:43.



This must be the auburn since it has springs I'm assuming?





Do these numbers mean anything?

















No springs like the other-is this a zexel torsen?

 

You scored the torsen

 

Not sure if you can see well enough by these pics but do they look ok? To me nothing looked out of the ordinary-gears looked fine with no metal shavings.

 

You got one Auburn and one Torsen. The Auburn has a 2.73 on it. Can't tell what the other one is.

 

thanks for the thread, let me know I got a good rear for my car. Never knew how to tell torsen vs auburn until I read this. (got mine for free from a dude that wanted a "junk" car out of his driveway lol.)

 

I didn't notice before, but the rear end with the Auburn has a bearing cap stud kit in it.

 

It looks like the Pinion teeth has rubbed on the auburn diff? It looks like teeth-marks on the diff centre, no?

 

Either the pinion nut came loose or a pinion bearing failed at some time. I've seen them a lot worse than that.