*Median odometer reading when the problem happened, where owners gave one. One complaint can name several problem areas.
Service brakes
The contact filed the complaint on behalf of the owner of a 2021 GMC Sierra 3500. The contact stated that while the vehicle owner was driving at an undisclosed speed, the driver noticed that the rear wheels were attempting to lockup. The contact stated that the failure was noticeable while driving forward and while reversing. No warning light illuminated. The vehicle was taken to the independent mechanic, where it was diagnosed with detached rear brake pads and detached rear emergency brake shoes. In addition, the rear brake caliber had seized. The vehicle owner was informed that the rear brake pads and the rear emergency brake shoes needed to be replaced, and the rear brake caliber needed…
May 28, 2026 · 140,606 milesPower train
During takeoff the transmission acted as if it was in neutral while I was crossing traffic luckily, the semi truck that was coming towards me was able to stop. I had the vehicle towed to a shop. After the vehicle was towed to the shop the transmission acted normal when the mechanic searched the VIN number. There was a service bulletin issued by General Motors for this exact problem. Had the semi not been able to stop. It couldâve very well killed me or my children. I suppose if it wouldâve killed someone, maybe general motors would finally do a recall for this very disappointed in general motors and the NHTSA, the fact that this is an ongoing problem and has not been fixed and as a…
Nov 21, 2025Electrical system
The contact owns a 2021 GMC Sierra 3500. The contact stated that while his wife had the vehicle idling with the rear defroster activated, shortly afterwards, she observed smoke coming from the plastic on the rear sliding window. After a visual inspection, the contact's wife observed that the plastic was melting, prompting her to deactivate the rear defroster. No warning lights were illuminated. The vehicle was taken to the dealer, who was unable to determine the cause of the failure. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 26,000.
Sep 1, 2025 · 26,000 milesBack over prevention
The contact owns a 2021 GMC Sierra 3500. The contact stated that while reversing, the back over prevention camera screen displayed an image of the ground. The contact stated that the image was approximately ten feet behind the vehicle. The vehicle was taken to the dealer; however, the failure was not duplicated. The dealer replaced the back over prevention camera system, however, the failure reoccurred. The contact stated that the original back over prevention camera was installed in another vehicle, and the back over prevention camera system worked as designed. The contact was informed that the back over prevention camera was not the cause of the failure. The manufacturer was made aware of…
Jul 14, 2025 · 70,000 milesUnknown or other
There is a known issue with these trucks with the infotainment screen blacking out, which renders the backup cameras inoperative. This is a huge safety risk and its astounding to me that this hasn't been recalled yet.
Sep 30, 2024Unknown or other
Vehicle is put into park after driving. Shift to Park warning comes on while vehicle is in park. Vehicle will not shut off due to this warning and must be left running unoccupied.
Feb 3, 2025Electrical system
When carrying the electronic key in my pocket the vehicle will lock/unlock presumably due to the remote contacting other items in the pocket. I have owned well over a dozen GM vehicles and never had this issue. I believe the remote design has the lock/unlock buttons too proud of the surrounding surface
Jun 1, 2024Power train
The contact's son owns a 2021 GMC Sierra 3500 Commercial Vehicle. The contact stated while her son was driving at an undisclosed speed uphill, the vehicle failed to shift to a gear higher than 5th gear. Additionally, the rear wheels locked up, causing the vehicle to come to a stop. The driver attempted to resume driving, but the vehicle failed to exceed 10 MPH. The contact was unsure whether a warning light had been illuminated. The vehicle was towed to the residence of the driver's girlfriend. The vehicle was then towed to the dealer, where it was diagnosed that the failure was related to NHTSA Campaign Number: 24V797000 (Power Train); however, the part to do the recall repair was not yet…
Nov 10, 2024 · 133,000 miles
Owner complaints are submitted to NHTSA by the public and are not verified. Shown as filed (NHTSA removes personal details); long reports are shortened.