2008 Silverado 4.8L. When I’m out driving dirt roads for a while I try and drive up a steep hill and the truck has little power and will not even spin a tire, and just stalls. Then I’ll drop it in low and put the pedal to the floor and it just Revs up real slow and the truck doesn’t move, or spin a tire.. Then I’ll try 4 high and the truck still won’t move even when I floor it. So I put it in 4 low and it does what it’s suppose to and has plenty of torque and power. No codes
thrown! Any help?? Please! I just replaced the transmission and it still does it. 187,000 miles. thanks for any help?

 

sounds like a failed transfer case.