Help I have a 01 Denali has 117,000 mi it started out acting like a transfer case issue banging when turning then one day it started slipping a little then lost rev
Then forward if you turn it off and let sit for 5 min it will move just fine for 5-10 min but also if you shut it off and restart it won't move if you cycle the key you can sometimes get it to move again
If anyone has any ideas please let me know

 

I'm sorry that I don't have anything much more than a clarification...

You're right in moving past blaming the Transfer Case. Though electronically controlled, it is a mechanical device, and either in gear or not. If (in 4WD-Lo) the Chain started slipping on either Sprocket, you'd think your ride was about to explode !

Noise when turning usually indicates a Differential Gear problem (if open).
Slippage (in 2WD) also may be caused by the Rear Differential (if Eaton or other type Limited/True).
Have you experienced the same problems when it's in 4WD ?
Have you by chance tried to put the Transfer Case in Neutral ?