GMC Complaints

Per GMC dealership, this vehicle suffered a Transmission valve body failure and they are recommending replacement of the entire transmission.

P1098 code for coolant control valve malfunction causing a radiator leak. Should be covered under warranty, but Wyatt Johnson in Clarksville Tennessee giving me the complete run around trying to get me to pay $3500 for a radiator replacement.

i had taken care of the recall items in regards to the failing 6.2L engine. I was driving on the highway (going ~70mph) when all of a sudden the car kicked into neutral and the engine shut off. I was able to pull over, but the engine would not turn on. Electronics worked, but I think i had a total engine failure at 42k miles.

2026 Yukon Elevation with 3,957miles. I was driving down the road and pulled into the turn lane at an intersection. Vehicle cut off with the Auto Start/Stop function and would not start back up. I continued and tried to restart the vehicle but would not start; I was blocking the lane with cars continuously going around me. Vehicle stated service transmission on the display- I was unable to put it into neutral to push it out of traffic; You are only allowed to put it into neutral when crank and couldnt get the accessory mode to come on without the vehicle trying to start. I called the local police department and they sent an officer to direct traffic until a tow truck showed up. Both observed the vehicle not starting. There were no symptoms prior to the vehicle cutting off, only once auto start/stop initiated did the vehicle not restart. Vehicle will be sent back to the dealership tomorrow to resolve this issue. I have dash cam footage of the incident and photos of the display on the screen.

My engine seized up on me on the highway. I was stranded and couldn’t start the vehicle and it was freezing outside.

Transmission problems, loss of power. Put a reader on car and said it was a selinoid. Replaced that and now it has happened again

On 2/4/2026, my vehicle (2019 GMC Sierra AT4 and VIN # 3GTP9EED5KG240494) experienced a catastrophic failure of the engine oil cooler lines. This is a well-documented manufacturing defect involving the failure of the crimp joints between the rubber hose and metal tubing. This failure occurred abruptly, causing massive oil loss and posing a severe safety risk due to the potential for sudden loss of oil pressure and engine seizure while operating the vehicle at highway speeds. This specific component failure is recognized by General Motors under Customer Satisfaction Program (CSP) N212326940. GM explicitly acknowledged this failure as a manufacturing defect. Despite the fact that the defect is inherent to the part’s design—and not a result of typical "wear and tear"—GM has denied my request for reimbursement, citing that the vehicle is outside the standard 36,000-mile warranty period. I exhausted all good-faith efforts to resolve this through GMC’s internal escalation process. I spoke with a representative and a supervisor, both of whom refused to honor a reimbursement request based on the manufacturing defect. They refused to consider that the defect, as documented in GM’s own internal bulletins, is independent of mileage and that the repair was performed at an authorized GM dealership. I am seeking full reimbursement of $2,171.58 for the repair of a known, safety-related manufacturing defect. GM is failing to stand behind their "Professional Grade" standards by refusing to cover a part they have already admitted is defective. I request that your office mediate this dispute to facilitate a full refund of my out-of-pocket repair costs.

When initially turning the vehicle on for the day and turning on the heater, the cabin fills up with exhaust fumes odor. This also happens while the car is idling and not moving. Have taken it to the dealership and they do not know how to proceed or what is wrong with it.

The motor went to knocking and lost power. Cost us about 3500. To fix. Lifters went down cam went down which caused major motor knock and loss of payer

I’ve gone through two transmissions on my 2018 gmc sierra 1500 both times the same issue. The gears are shot, hard shifting. Vehicle is well maintained. Both transmissions one original equipment and second bought at the dealership the truck was bought both only lasted over 80000 miles. Driving the truck loss of power or torque is noticed, then a hard shifting. Checked fluid all was good not seeing metallic shavings. Then the overheating of the transmission, faulty valve replaced with aftermarket bypass and did transmission flush. But each occasion there was an incident I would’ve driving on the interstate and vehicle would lose power and almost hard stop and cause a crash. Then vehicle would only go in reverse both times the transmission gave out. The only warning light that ever came on was a transmission overheating and nothing else. I’m currently in the process of having to get another transmission because of the same issue again. Vehicle was seen by a technician and deemed the transmission was shot again.