2014 GMC Sierra Transmission and drivetrain Problems

“The truck was averaging about 20 mpg but shifting erratically like it couldn't decide what gear to be in. After using the 4wd the first time the mpg dropped off to about 17 and has been declining steadily currently I get 14 to 15 mpg and drive 150 miles per day mostly highway. I have taken it back to the dealer twice they said the computer couldn't get used to my driving style and reprogrammed the computer. When I took it back about the mileage a guy came out and said he could tell if something was stuck and switched the 4wd a few time and said it was fine. …”

“My vehicle started with a vibration on or around 12,000 miles. The vibration slowly increased as time went on. I made appointment with the dealership where the vehicle was purchased.(capitaland motors) at this time the vibration was strong enough to vibrate the back window. It would start at 30mph and get worse at 45mph. The mechanic checked balance and road force the tires. But told me that the vibration was normal and he could fix my back window. I called Gmc and filed a complaint. They told me to take it to another dealership. I did on 11/25/14. This time I took it to goldstein buick-Gmc. …”

“I have had my truck back the dealership 8 times for the same problem a vibration that you can feel in the seat steering wheel and gas pedal, they have had the factory engineers out three time and looked and worked on it, first time the engineer did a couple of things and said that it was up to factory specs and that was all he could do, I drove it home and before I was a block away I could tell that they did not fix it, when I got home I called the dealer back and told him so he called GM and the next week they sent out the same guy and this time he worked on 5 or 6 other things that he did…”

“Driving down the road aprox 45- 50 MPH transmission kicked into neutral causing vehicle to slow down suddenly ,almost got rear ended due to sudden slow down . No where to pull over , after letting off the gas kicked into gear and got it home.”

“Vehicle was purchased new from a dealership. The vehicle is modified and sold commercially under the rmt (rocky mountain truck works) package. The package includes modified suspension and lighting. When accelerating, the transmission fails to shift into a passing gear causing the RPM(s) to exceed 6000 at which point the rev limiter shuts down power to the vehicle until the RPM(s) are back in a safe operating limit. The first time this happened, I was attempting to pass a vehicle on a secondary two lane highway. …”