[dabowla]

I have a 2007 silverado and am having a problem with the 4wd. For quite awhile the 4x4 would just stop working then i would let it sit for awhile and then it would be all good again. Recently the problem is that the selector switch would indicate 4lo but it would not be in 4wd. Would shift like it was in 4lo but no power to front wheels. I have changed selector switch and cleaned the ground under drivers side with no luck. Brought new TCCM and now the lights on the selector switch wont come on and code u0102 comes on which is unable to communicate with tccm. Truck I believe has defaulted to 2wd cause shifting is now normal. Have read on here about the actuator and encoder motor but wondering how I could text these parts before I buy new ones. If I put the old TCCM back in the 4lo light comes on but trusck is still in 2wd. service 4wd warning comes on all the time.

 

[Billy03z71]

Having the same kinda problem with my 03 also, might have to bite the bullet and take it in after a few failed attempts to try and fix it

 

[JuniorE]

Have you checked with the dealer to see if the is a software update that needs to be done. I had a 2007 that was also acting up and even though I would turn the dial it wouldn't shift out of two wheel drive, even though the light would show it had. It happened so intermittently that I never dug deep enough into it to find out what was causing it. I sold the truck and bought a 2014 Sierra, and this winter I had a problem with the new truck. I had it in 4x4 when I drove up to a cottage to go snowmobiling and was parked for 2 days. When I went to drive home it was stuck in 4x4 and wouldn't shift out. No matter how many times I tried it just wouldn't change. The truck is still under warranty so I took it into the dealer, that's when I found out that there was a software update that had to be done. It has been fine ever since they did it. I also recently received a letter from GM regarding my old truck that mentioned that I should bring it in due to an issue with the 4x4 having shifting problems in colder weather. I know everybody hates the dealer but you might want to start there before spending anymore money on parts.