4th Gear Limp Mode
 

Hi guys. I am having an issue. My truck is acting up. When I start it the only gauges that work are oil pressure and voltage gauge. Everything else is on zero. Prnd321 also not lit. When shifting from park to reverse or drive it snaps and truck lunges. I only have 4th gear. Engine will rev past 2000 rpm just won't shift. I have no DTC's when I scan. Replaced NSBU with no change. Any ideas?:humm:

I've had that issue on a few 01s and a few 03s. The problem on all of them was the neutral safety switch and both connector pig tails. I replaced all three components from GM and that corrected the issue on all of them. Another thing that I have heard about but haven't witnessed yet is a gound wire on the left frame rail under front of cab needs to be cleaned.

mine wasn't that bad but cleaning the ground QuickCarl talks about helped. there is also a DIC fuse in the fuse box. you could try that for your cluster