Background info:
2005 TrailBlazer LT with 4.2 i6, G80, 3.73's
Bought with 99k miles on it. 4 wheel drive switch worked, and 4 wheel drive did as well. Tested 4HI and 4LO worked awesome. At 100k miles I had the front and rear end fluids changed, and the transfer case drained and filled with...