Special gear lube for GM posi?

Howdy, I heard that there is a special lube or additive that I need for a gm 12 bolt posi. I believe its a chevy and I know its a passenger car rear, if that makes any difference?

Anyone know? I figure its better to ask then to just dump 80/90 in and hope for the best.

Thanks.

 

Best to go to GM dealer and get the additive. Or burn up the clutches !!!!

 

Red Line make a friction modifier for clutch and plate differentials, they also make 75/90 with the friction modifier allready blended in the oil.

 

GM used to make a special rear end lube just for posi rears but now the GM Multi Purpose rear end lube is for all of them including posi rears. The GM additive is still needed though. The Red Line products are also compatible with the GM posi clutchs.

Tom

 

GM part number for positraction additive is 1052358.