Transmission is locking up and making rear wheels violently shake on the highway at high speeds. There is a TSB for the trans valve body on 2020-2022 but it's doing the same for my year and every year with the new 10 speed Allison. It will put your vehicle in power reduce mode as well. I've had a 2020 do it and now my 2023. GM said there is no issue unless they can duplicate it and it does it randomly. So ridiculous for a $90k truck to have issues and then not be able to help.

- Clermont, FL, USA

We were traveling to our cabin in Southern Utah when the Transmission Control Solenoid Valve stuck in an "on" position. We were unable to accelerate more than 55 miles per hour. We stopped in St. George and went to the Chevy dealer for a fix. We were told that they could not get to our vehicle for 2 weeks AND the part is on national back order for 6 weeks. Clearly if it is on national back order, this is a major problem in GM trucks. Our truck is still under warranty and Chevy would not help. We were 130 miles away from home. It was too expensive to tow, no rental cars were available and plane tickets were too expensive. We "limped" the truck home to Las Vegas at 55 mph. Speed limits on [XXX] range anywhere from 65 to 80 mph and there are no back roads. Those speeds are deadly when we could only accelerate to 55. 3 times we were almost rear ended by semi trucks because they came up behind us on a curve at 75 mph. This part failure can be deadly. Fortunately, it was daylight and weather was mostly clear. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Las Vegas, NV, USA

Transmission had a hard shift which jolted the truck switching gears to a lower one unexpectedly. It caused my body to jerk back. It happened 3 times. 2 were mild but the 3rd time was extreme. Always while accelerating. Average speed was about 50 mph when this occurred. Dealer has confirmed a failure of the transmission valve body. If the transmission were to be put in park while traveling, it could cause major accident and injuries. After the 3rd time the engine warning light came on and the truck went into limp mode.

- Blaine, MN, USA

I received a p0747 and p0700 transmission codes on my GMC sierra 3500. It would not engage above 3rd gear and I almost was rear ended by a Semi truck because I was unable to speed up. The vehicle CEL turned on and "Engine power reduced" notification appeared on my cluster. Engine RPMS were at 2800 rpm and my speed limit would not go past ~40mph. I currently have my vehicle being inspected by the local dealership. The vehicle currently has ~19,300 miles

- Elko, NV, USA