[PxTx]

Sounds like lots of aftermarket parts. Don't take this the wrong way, but how do you know it was a factory GM posi? If you've got a PN, we can probably lookit up and tell you what it is.

The bolt-in axles are also suspicious of aftermarket too. There were some non Chevy GM rears with bolt in axles but I'm not aware of any "service package" rears that used them.