I know this has been discussed here, and I did a search, but didn't find anything. Is there a special fluid that should be used when re-filling a posi diff? I used to use 80-90 Gear oil, but I think there are some better products now. Thanks for any info-

By the way- it is not a fresh re-build or anything, just had been out of the car for a a while.

Nick

I used 75w-90 Mobil 1 synthetic gear lube with one bottle of GM posi additive in my 12-bolt with an Eaton posi. No problems or noise for over a year now.

Rod