i went to pepboys yesterday and got to chatting with my friend that works there. i told him i was gonna do a t-case fluid change in the near future and that i needed autotrack 2 from the dealer. he told me i could use the Royal purple-synchromesh stuff from manual transmissions. he said it was almost the same crap, and that hes known people to put that in the newer GM t-cases with no problems. what do you guys think.

 

I'd stay with what GM recommends, being as you have the AutoTrac. Not quite the same as the "regular" transfer case.