I just finished swapping the rear end, it came off a 99 camaro z28 6 speed which apparently had 3.73s. Nothing to confirm though so I shall assume it has 3.42s like the stock one.

So I put the rear end in my 88 iroc nice brakes etc... sweet! But... I spin the yolk on the rear end and only one wheel is spinning... I thought all these rear ends had posi??

I haven't seen the car it come off of in person, but the dude had videos and all..

Is it gonna one leg doing donuts? Or is it gonna one leg doing a burn out?? Is the posi worn out?? I don't know...

Also I just purchased an adjustable panhard bar, will it fix my issue of the wheel sticking out more on one side?

Thanks..

 

When you changed the fluid like any sensible person would when installing a used major part, and counted the gear teeth so that you knew for sure what gears it has, what carrier did you see?

 

The one wheel spinning means it's either an open diff or a govlock. A govlock is not a posi but it will lock up both wheels when one starts to spin. The downside is the locking teeth are small and weak and they can break.

As mentioned above, pull the cover, change the fluid, count the teeth and examine the inside to see what's actually in it. There's always a possibility you bought an open diff.

Take pictures. It's easier to identify.

 

Posi is bad or it's a v6 rear. Or both.

 

I believe early 99 rear may have an auburn unit which is a clutch type posi. It could be shot and thats why its one wheel peel

Most 99-02's had a zexel torsen diff which is a worm gear posi. It wont one wheel peel unless its broke but you'd beable to tell

Early year 4th gens likely had auburns or something else i'm not sure

Or its a v6 rear

I agree with sofa, you should have checked the diff and swapped fluid out. That tell you what you got

 

IIRC, Auburn differentials were only used on late 4th gens, and ONLY on SS's and Firehawks as it was an SLP option, and NOT a factory GM option. They were fairly rare as well, but really not all that desirable as they really weren't any stronger than the anemic factory 10 bolts.