GMC Complaints

This 2018 GMC Sierra has 100,000 miles on it and in April 2025 the transmission went out and needed a new one. Now in July 2025 the engine has lifter failure leading to the need of a new engine.

Engine defect where engine can fail during travel. There is no known solution or proper notice given to me of any kind.

Dropped my 2022 Yukon Denali off May 7, 2025 to Mike Reed Chevy due to failed transmission. Order was placed May 15, 2025 for a valve body part. Multiple phone calls were made without success on status of repair. I was forced to drive to the dealership for answers on June 10. I was told that due to my car being under warranty I am at the mercy of GM. The Part needed is apparently on indefinite backorder. Contacted GM to expedite part and was told it could be 3+ months before I can expect my car back. Claim number with GM is 55328239. After doing research, there is over 2000 people who are experiencing the same issue. Mike Reed Chevy nor GM offered assistance with a rental to offset the inconvenience. It was only until I demanded to speak with the service manager that I was given a rental car. As someone who manages a hospital, the delay in obtaining this part has caused significant hardship, and to date, there has been no clear timeframe provided for when the part will become available or when repairs can be completed. As a consumer, I am left without reliable transportation as the dealership has requested me to return my rental. The lack of transparency or timeline for resolution is deeply concerning. This has not only impacted my ability to fulfill daily responsibilities, but has also raised broader concerns about the availability of necessary vehicle parts and the protections in place for consumers in similar situations. I am seeing guidance or intervention from your office to help expedite this matter, whether through direct communication with the manufacturer, identifying legal remedies available under consumer protection laws, or advocating on behalf of consumers facing unreasonable delays in vehicle repairs due to supply chain issues. Any assistance or direction your office can provide would be greatly appreciated.

My 2021 GMC Sierra 1500 Diesel Truck is displaying the Check Engine Light which I was told by the local Mount Vernon GMC Dealership is a failed Temperature Control Valve affecting the transmission. I also get a warning message of "Reduced Engine Power". I am told that it is OK to drive the vehicle but at reduced power. The dealership told me they ordered a replacement part which is covered under warranty on May 7, 2025, but showed on "Back Order". Every time I call to follow up on the status, I'm told it is still on "Back Order", and they cannot do anything to improve the delivery. Why does a customer, owning a "Denali" truck under warranty, can't get the problem resolved? I have a recall notice from GMC dated January 2025 about this very problem and have shown it to GMC dealerships during regular services, and still have the problem. Since I have bought this truck, I have experienced a failed right running board that cost $1,500 to repair a few months ago which is failing again. The driver side mirror now vibrates when I put the truck into drive after being in reverse, and I cannot get any idea on when this transmission valve problem will be fixed which is causing me serious delays in using the truck to pull a trailer. Prior to this problem I had the dealership replace my brakes which required 2 follow-up repairs due to the "GMC original rotors" being warped that required machining to make them not vibrate which to me, now makes them "used". This means I paid full price for "repaired" parts! I thought that by buying a GMC "Denali" 1500 Sierra truck I was buying the "top of the line" in pick-up trucks but now finding out it's a lemon. I love the truck, but not the problems. What do I need to do to get this fixed? [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

My 2025 GMC Denali EV has experienced repeated safety-critical issues, including severe torque pull under acceleration, making it difficult to maintain safe lane position and compromising steering control. This behavior persists even after inspection and is documented on video. The vehicle has also had repeated service brake assist faults, including one critical failure at under 6,000 miles and additional incidents that resulted in me being stranded out of state. Additionally, I have experienced ghost braking while reversing, where the vehicle unexpectedly applies brake force even when parking assist features are manually disabled. I have performed comparative testing with an identical Denali EV loaner (same year and build), as well as three dealership test units, all of which exhibited proper steering stability and regenerative braking behavior. My vehicle’s issues are therefore not “normal operation” but clear, reproducible defects that affect both safety and expected vehicle performance. These issues raise major concerns for real-world safety scenarios requiring immediate acceleration (e.g., merging onto highways or avoiding fast-approaching vehicles). My documented comparative evidence and repeated attempts to have the defects addressed have not resulted in a safe resolution.

Leaking transmission fluid- transmission fluid all over the underbody of my car. No reason to be leaking. Can’t find where it’s coming from. Every time I park than move to leave there is a puddle of transmission fluid.

Trailer Brake Controller displays message on Dash intermittently that the trailer brakes are disconnected, and after a short pause it will say reconnected. This occurs multiple times a day. This did not occur with my previous GMC. I do have solar panels and Lithium batteries

Truck is at the Jim Gauthier GMC dealership on Mcphillips in Winnipeg, Canada. Engine endured catastrophic failure and is currently waiting for a new engine.

I was at a stop on my street needing to cross a busy one. I stepped on gas to quickly move forward and it stalled. Almost causing a wreck. I have taken it in to gm it had a recall and they said it was fixed and now there is another recall and it has been at least three months now that our dealer can not resolve this issue because they do not have parts to fix the issue. The vehicle seems to struggle moving forward and when its switching gears. It is still running but I feel like something is off. I have two small children with me and we are in this car all the time. I do not feel safe driving it anymore. What can I do about this?

My 2018 GMC Yukon SLE has a Transmission Failure and a engine oil coolant failure. The issues occurred while driving when the vehicle had to go into limp status to prevent the transmission from complete failure. I have taken the vehicle to the dealership 2x and they changed the fluid once and replaced the thermostat the second time. Neither case fixed the vehicle, it is currently in the shop for transmission and radiator w/ engine oil cooler replacement - $8200 The vehicle has been inspected by Aamco of Dover, DE and is awaiting inspection by warranty company 3rd party inspector. There are no warnings before the system is overheated and goes into limp status and at that point an alarm sounds in the car.