I’ve been doing research on this forum but haven’t found a problem quite like mine. Just swapped a 99 lm7 with a 4l60 and I believe np8 transfer case (push button switch). I have the motor running and have not yet installed my wiring for the transfer case to use 4wd. The problem is having is I can manually shift into all gears (reverse,drive, 1,2,3) and will drive if I manually shift but when I’m in drive it will not shift out of first gear no matter the rpm. Any ideas? I’ve heard maybe vss, stuck shift module? Also wondering if it is vss if not having my transfer case wired up yet would have any effect? Any help would be greatly appreciated. I’ve checked my plug going to the transmission and I am getting power and the transmission is making a good ground to the block.

 

you don't have anything wired up to the transfer case? That could very well be your issue. The speed sensor the PCM Uses for shift timing is actually mounted on the transfer case, not the trans.
I'd be sure to check data using a scanner or HPTuners to make sure you have speed signal and to check what commanded gear is by the pcm.

 

It’s fixed, thank you I’m an idiot. I didn’t even think about it not getting a vss signal by not having the tcase wired up. I bypassed the tcase harness and plugged my engine harness directly into the vss and it’s shifting great now. Thanks!

 

Happy to help.
I see you're from Lincoln.
I'm from the sioux city area. Ever get to the races at I29?

 

Yeah sometimes we go down there!