It Won't Downshift

[rrroach1]

Hello everyone, I have been searching for an answer for this one. I have a 06 1500 4x4 with a 5.3 engine. No matter what speed I am moving and step on the throttle it will NOT downshift. From a stop it will upshift fine, just wont downshift. I have had a scan run on it an has no codes. Local mechanic is stumped. Cant find anyone who even know for sure how the kickdown really works on newer trucks. Any Ideas? Thank you.

[jro909]

solonoid in the trans maybe

[nickvrebel]

I don't know the mechanical of the transmission, but I do know how a downshift is commanded.

 

There is a bunch of parameters in the tune that will command a downshift, basically it all boils down to engine load vs. throttle position sensor vs. current vehicle speed

 

the little bit I do know about the mechanical is that there is a bunch of solenoids (as mentioned above) that area accessible (and often damaged) by removing the transmission pan, these solenoids mechanically tell the transmission what to do, it sounds like they aren't reacting for one reason or another.

 

Any one with a good tuning package (HP Tuners, EFI Live, etc.) could ride in the truck and manually command a shift and see if it's the computer not commanding it or if it's a physical problem, but I would bet on a physical issue.