I wanna know if my car has a posi rearend. It's an 85 iroc with the GU6 rpo code which says 3:42 performance rear axle. it doesn't state whether it's posi or not. i got the #'s off the axle and i can't find them anywhere for any 82-92 fbody. it's 9EP. I would just jack up my rear end and spin the tires w/ it in neutral, but the posi is probably bad if it had it. (137,000 miles on it)

 

if you want to know for sure, 100% sure pull the cover and look. no other way to know or check. the numbers are pretty meaningless after more than 15 years.

 

Does the code G80 appear on the list (posi).

 

no, the rpo code for my rear end is GU6. if i pull the cover, i'm gonna have to put gear oil back in the rearend cuz it's gonna leak out, right? Also, how will i know it's posi just by looking at it?

 

No RPO G-80=NO LIMITED SLIP IN THE REAR AXLE. Now you don't have to pull the cover.

 

But, the previous owner might have installed a posi.... so he might want to pull the cover just to check! (Watch out, the lube stinks...)

 

it doesn't really matter much anyhow. in about a month, we're pulling out the rearend and tranny(as soon as i finally finish painting it). the bearings in the rearend are going out. i'm gonna rebuild the rearend and definately want to go with posi. any recommendations...?? probably gonna go with 3:42 gears again.

 

Buy the SLP one for $99 before there all gone. Just curious what engine and transmission is in your car and was it stock???

 

buy the SLP one what?? my car has a 305 TPI motor(730 SD) and 700R4 tranny.

 

SLP sells the zexel torsen posi's they took out of Z28s when they made em into SS's its a torque sensing limited slip...a pretty good unit. It accepts 3 series gears 3.23 and up but you will need 28 spline axle shafts from a 89 or later 10bolt. Unless you are gonna take the car to the strip a lot stick with the 3.42's I'm very happy with mine

 

ok, my car is an 85 iroc. i'm pretty sure i have 26 spline axles. will the gears i have work with the posi unit? also, you said i have to get axle shafts from an 89 or up? what about the axles? or did u mean axles? also, where can i order the posi unit?

 

if your rear is stock you have 26 spline, yes by axle shafts we mean axles, one for each side. You can order the Zexel Torsen take off posi from SLP at www.slponline.net or do a search for zexel torsen on yahoo or your favorite search engine, some other companies were selling them for about the same amount, around 100 bucks. Your stock 3.42 gears will fit, as long as they are in good enough shape to reuse, if not try to find a complete 10 bolt from a 89-92 v6 and rob it for shafts and gears. also remember to get an install kit so you can set the backspacing up right and get new bearings! its worth the money to do it right.

 

I just looked on slp's website and the zexel posi unit was listed for like 499.00. where on there is it for 99? Also, will my housing for the rearend work (eg, i have to just get 28 spline axles from an 89-92 10 bolt thirdgen) i'm gonna get a rebuild kit also. can i get one off slp's website too? if not, where?

 

Zexel Torsen OEM Differential p/n: 64501T $99.95

This is the OEM posi in later model 4th gens, SLP replaces it with the HD Zexel (the $500) in the SS.

You shouldn't have to swap housings, and I wouldnt unless there is something wrong with the one you have, but thats because yours is set up correctly for the brakes in your car. If you cant get the rebuild kit from SLP get it from Jegs or Summit.

 

hey, thanks for the info. for some reason, i couldn't find it on slp's site. i'll probably order that for now and maybe get the 500 dollar one when i get a better rearend once i start modding it.