I have an 84 Z28. Rearend ID begins with 6HF. I looked and it says its from an 89 w/3.08 posi. Ok, weird but understandeable. Then I free spun the tires, they turned opposite directions. Dosen't that mean it's not a posi? The haynes manual dosen't list this end in 84.

What is it? Is it a posi? Is it a 3.08?

 

Dump the cover--the fluid probably needs to be changed anyway--and take a peek. The following FAQ discusses gearing and limited slip:

https://www.thirdgen.org/forums/tran...-10-bolts.html

JamesC

 

These rear ends had the Auburn and the Governor Lock in them. If you have the Governor Lock then you either didn't spin it fast enough to cause thee governor to lock, or it's broke. If you have the Auburn then it's just palin worn out and must be replaced. You can not rebuild the Auburn, and I wouldn't even try if you could. They are junk.

The ONLY way you are going to know what you have is to remove the cover and look at it.

 

Does this mean that my rearend is from another vehicle? Is the Haynes manual incomplete?

 

No, the Governor Lock and the Auburn were both factory installed differentials in these cars. You are going to have to remove the cover and see what is in it.