when I washed the car ice formed under it and when I tried to back into the garage it just spun the driver side wheel so I put it in first and it spun the pass side wheel.I thought an 82 z28 would have a posi does it not or is there something wronge?I havnt been able to get the car to the road to see what happens on dry asphalt.If there is something wronge would it be easier to change the whole rearend or just the guts.I have access to 2 different 3rd gens to get parts.I really dont want to pull the whole housing.Are all 3rd gen rearend guts interchangable or only certain ones.

 

Find your RPO code sticker and look for G80 in the list. No G80 = No Posi. Posi was actually an option through cheap old GM. Also, maybe your rear end isn't the original and was swapped with an open diff. Jack it up and spin the one wheel and see what the other one does.

 

Yeah I jacked it up spun drivers drum pass did not move.I cant beleive the guy that put the motor in it would not have put a posi in it if it didnt come from the factory with one.I am the third owner of this car the firsst one works for one of the premiere engine builders in the northeast.he has worked there for 30 years.he wouldnt put a 500 horse motor and a aluminum muncie in a car with a open rear end.2nd owner was a rich guy who drove the car maybe twice a year for the last 12 or 13 years.If I had to guess one of owner #2 employees took the car out and hurt the rear end and left it in the condition it is in or fixed it with what ever he could get his hands on quickly. where could I find the rpo code sticker?

 

Yea, 500HP motor(??) and spin your wheels on ice and now cannot find the RPO sticker. The Limitd Slip (posi to you) was working as designed.

 

Shouldnt there be a tag on the rear?

 

there is a stamp in the front passenger side, but after about a year, the numbers are no longer legible. some have a tag, and if they have ever been opened, most of the time it doesnt go back on. the limited slip in my camaro was damaged and locked both wheels together. i thought thats what they were supposed to do until i learned how they are supposed to function. when there is no torque load (i.e. jacked up and spun by hand), it will act like an open diff. its only under load that they will spin both tires. my blazer has a limited slip. sometimes it spins one, sometimes it spins both

 

I wasnt sure if a limited slip would act like that.Thats why Imentioned not being able to get the car to the road to test it.We have almost two feet of snow on the ground and snow in the forcast everyday for another week.I was thinking maybe pulling the cover take a peek if nothing is obvious fill it with new fluid and wait for spring.The fluid needs changed anyways.Thanks for the info.I will post what I find when I look inside.thanks for the info guys.

 

If you have RPO G80 (Limited Slip) it should like this.

 

Your RPO code sticker is either located on the underside of the center console storage bin armrest or on the inside of the lid for the rear storage bin located on the rear left trim pannel. They are in alphabetical order. Look for G80 for a posi rear end. Pullingthe cover is for sure the best way, while your in there count the teeth on th ring gear and the pinion to confirm what gear ratio you have.

As for spinning on snow or ice, my wifes Jimmy, my Dodge pick up and my Camaro will spin both tires right away if you step on the fuel.

 

Depends on which type of Posi you have. A Govlock rear end (commonly refered to as a Cookoo clock rear end) will allow one wheel to spin first untill the springs wind up applying preasure to the clutch's to get the other wheel spinning. Jacked up, you can spin one by hand and normally the other won't spin.

The rear ends in third gens are usualy Aubrns which have side force constantly applied to the clutch packs through pressure springs placed between them (See above picture). This means the wheels are basicaly locked togeather unless one wheel needs to spin faster than the other such as on a corner. The outside wheel spins faster than the inside and that causes the clutch's to slip allowing for smooth action in the rear end. Once both wheels reach the same speed again the clutch's stop slipping and everything drives as one unit again.

All 7.5 and 7.625 rear ends (3rd gen camaro, S10 blazer/Jimmy) are Auburns, but can be upgraded to Eaton. Both work the same way except the Eaton can be rebuilt, the Auburns can't. Once they stop working they're scrap.

Govlocks are in 8.25, 8.50 and 8.75 rear ends (full size older pick-ups, Blazer, Jimmy ect.).


Hope this helps.