Well it did come out of a '99 v6, I guess if it was the original rear it would have to have been a y87 since it has limited slip. If that is the case then, according to a link someone posted earlier, it should have a zexel-torsen limited slip? I suppose the shop could have been wrong when they said it was a clutch style.

And if the owner has swapped it out then who the heck knows. Haha.

 

The posi rear came as part of the Y87 package but I think the RPO code could have been ordered separate.

 

Correct

 

I knew my old rear end was the source of a lot of drag while driving, but damn...here are some mpg numbers. With the old rear I was averaging 25-26 combined mpg, with the new one this last tank was 29mpg.