new built trans...no 3d or 4th!

[Yukon82291]

Just put in a built trans and converter from transdepot, goes like a bastard 1st and 2d but wont shift into 3d or 4th. im stumped, any ideas?
2001 gmc yukon 5.3 4x4

 

[afpj]

Programming ? Can't remember if the PCM needs to be programmed when u put in a new tranny. I had a new tranny & front diff put in simultaneously but it had to reprogrammed as the first time didn't take. Don't recall if the programming was for the diff or tranny or both.

 

[Yukon82291]

i gotta get this figured out quick

 

[livingez_123]

Call the trans supplier. If you fry it trying to figure it out, good luck with the warranty. Call them and ask them for help. in the mean time don't drive it.

Why would you need to reprogram the PCM? if it's the same trans (4L60E) just having the battery cables disconnected during installation should be good for it to relearn your driving habits. It's could be just a bad shift solenoid or a bad electrical harness in the pan

 

[afpj]

Why would you need to reprogram the PCM? if it's the same trans (4L60E) just having the battery cables disconnected during installation should be good for it to relearn your driving habits. It's could be just a bad shift solenoid or a bad electrical harness in the pan

Yeah I don't get it either. Had the tranny and front diff replaced together, & when I drove out of the shop I decided to try out the awd button but it locked into 4wd hi. The service 4wd message came on, so shut it down. On restart it was back in 2wd, so tried the auto 4wd again & same thing. Took back to the shop & they said PCM thinks I had 2wd only, so needed repgm. All ok after that. Original 4l60e replaced with same. Extrapolating from this experience might help op. never made it to 3rd or 4th gear since I tested the 4wd system right away..