Cadillac STS-V Series Forum Discussion, For those doing Rear Diff Service in Cadillac V-Series Forums; I was down at my dealer earlier conversating with the head tech (became good friends) and while watching him change ...
I was down at my dealer earlier conversating with the head tech (became good friends) and while watching him change the rear diff in an STS and helping him get the exhaust back under the car -- he mentioned changing the fluid in mine to what he filled the new one with
Dextron LS Gear Oil 75W-90, part #88862624
Does not need the additive.. him and his dad are big Corvette folks -- and reccommended this for my V.. he said its greatly reduced some of the issues with clutches. Also I realized just how good he is because he changed the diff out in that car in about 45 minutes.. Lol
Ironically just for info -- when one starts roaring/whining.. its replaced with a new one.. No core back to GM, no remanufacture.. new one goes in, old to the can.