I was hoping you guys could help me figure out if i have posi or not....
I don't have the RPO code for posi, but the car can leave 2 nice black strips on the pavement which i dont think is possible with a one-legger

Maybe a previous owner put it in? It seems like most Z28's should come with posi anyways, so im not really sure...I guess the only sure way is to pull the differential cover and take a look huh? Any input would be appreciated!

BTW - cars in sig.

 

Thats pretty much the test right there. Do a burnout and if there are two marks then its posi. There are RPO's for the rearends, but I dont remember them offhand, and I dont remember which RPO's had posi (I think G92 did).

 

you could always pull the cover and look. it'd give you a chance to change the oil and posi additive.

 

If you don't want to go through the trouble of pulling the cover off. You can just throw a jack under the rear and put it in nuetral and turn the tires. If they go they same direction it is a posi. Torque can make both tires spin. My TA was a peg leg at one time and it used to spin both tires. I was confused for a while until my buddy showed me that trick. It is a good Idea to change the oil though.

 

ok thanks for the replies guys, sounds like the easiest way would be to just jack it up....

(SIDE NOTE)
G80: Limited Slip
G92: Performance rear axle ratio

 

There should also be a tag bolted with the cover saying "Use only limited slip oil" or something like that. Not sure on the exact wording. The only way to tell for sure is to open it up, as a worn posi could act like an open, even off the ground.

 

also check all of your other RPO codes. I have a RED RS and mine says it was blue. It also said mine has 3.42 gears and i have 2.73s. it says mine has the stripe package and it dosent. And heres the kicker. It says i have the 2.8 5 speed i have a 5.0 and a 700r4. Somebody put in a new center counsel in my car. So check all of them and see if they match up with your car.

 

haha that's to bad about your RPO codes... my codes seem to be the ones that came with the car though, everything matches up... pinstripe, engine code, tranny code, t-tops, etc...

But I dont have the G80 (posi) RPO code... previous owner could have put it in so im not sure though...

A new one probably couldnt hurt anyways though, everything on my car was shot when I bought it last summer... had to replace the whole engine/tranny it was completly trashed