I was wondering if any of you guys have used aftermarket fluids such as Royal Purple or Redline when doing 4X4 service or if you just stick with GM recommended fluids for the differentials and transfer case?

 

If you have the AutoTrak transfer case, I believe that the GM blue fluid is all that is available for the transfer case...that's what I always use. As for the diffs, I use any synthetic 75w-90 that is available, usually Mobil1.

 

Im not sure what specific transfer case comes in the Silverado SS.

 

I believe, but am not 100% sure, that it calls for the blue GM AutoTrakII fluid, which nobody makes a substitute for, that I'm aware of.

 

I believe your SS calls for blue Autotrak II. The 07/08 AWD borg warner units call for Dexron VI. At least my Denali does. I'm flushing with Valvoline Dexron VI in t-case and trans this weekend.