[BarryGMC]

has anyone ever drained that stinky old oil out of their trans or rear end? GM put it in from the factory. Its MP 80-90 rated oil. Its the sulfur that you smell. The sulfur problem is a myth. The sulfur creates an acid if exposed to heat and moisture over time and is not changed. the acid eats the brass faster than the steel. But will harm the steel eventually. your anti freeze creates an acid over time also and will tear up a radiator if not changed out regularly. your motor oil will do the same over time also. that is why there is a time given on intervals for change, plus the mileage. the creation is expedited by the unburned hydrocarbons. So do ever what you want but when you crack open that bottle of gear lube and smell that smell its the sulfur. And the old MP 80-90 that gm specified actually has a higher content than the GL5.