GMC Complaints

Engine started missing out. After taken to dealer, cylinders 5 and 6 were filled with oil. New engine is needed, and is on nationwide back order as thousands of these are effected.

dash lit up with ABS, traction control, and ESC warnings. Technician stated the entire brake system needed to be rebuilt. There is currently no ETA on when the parts to be able to accomplish this will be available.

Odometer Fraud. The contact considered purchasing a 2007 GMC Sierra 2500 from a local dealer. The contact stated that vehicle mileage was listed as 159,000, but the Carfax report listed the mileage as 400,000.

Been working with dealership on engine performance for a year, recall is delayed because of no available parts. I had bought a warranty that replaced the lifters and cam. Also this year the transmission, radiator, pully and belt were all replaced. Engine blew up last night and is back at dealership. I paid $80,000 for this vehicle and have had major issue after major issue with it. Looking into seeing if it qualifies as a lemon. Lucky was going slow when it happened and it didn't cause an accident. Could not get the vehicle into neutral to tow it.

For approximately the last year (2024-2025) my 2020 GMC Sierra 1500 AT4 with the 6.2L engine has had noticeable ticking, knocking, and unprovoked shaking upon start up and idle. The pickup has stalled out at stop lights and intersections in the past, posing risk. In June (2025) the pickup was taken to a certified mechanic for inspection who suggested possible lifter or valve failure. The vehicle exhibits a persistent ticking sound from the engine, which I believe may be related to lifter or valve issues, similar to those reported in lawsuits against GM for 2019-2024 models and the recall for 2021-2024 models (NHTSA Recall ID: 24V-676). This ticking occurs regularly, including at approximately 54,500 miles, and raises concerns about potential engine failure or sudden loss of propulsion, which could be hazardous, especially at highway speeds. I have noticed approximately 2 quarts of engine oil usage per my last 2 oil changes (roughly every 6,000 miles). I recently had taken the pickup to a local GM dealership where they informed me that I am not longer covered under warranty and the recent recall is not applicable. I was advised to “keep and eye on it, and get a AAA membership”. I am aware of at least 10 class action lawsuits against GM for similar engine issues in vehicles like mine, suggesting a widespread defect. These issues, combined with the potential for engine failure or impaired vehicle control, warrant investigation to ensure driver safety. I have records of the ticking sound and can provide further details if needed. I am willing to cooperate with NHTSA for inspections or further documentation.

Radiator cracked along outer edges. Similar to previous TSB’s as released by GM, but my vehicle doesn’t fall under the years covered by that TSB

Around 7k miles on the vechicle, driving down the road it kept coming to a stop and skipping. Pulled into the parking lot the best that I could and put it into park. After it wouldn't shift into anything. Never gave any dash signals. It is currently in the shop getting a whole new transmission.

I bought this car used and had only had it about a month when I was driving to work and was in slow traffic on the freeway when my car slowed to a stop despite the fact that I had my foot on the gas pedal. It turns out it was a transmission failure. My safety and the safety of the drivers around me were put at risk because I was unable to move my car over to the shoulder and out of the lane of traffic. Traffic was slow but was still moving. My vehicle is available for inspection but I’ve already had it repaired so I no longer have the faulty transmission. The problem was confirmed by an independent service center where I had it repaired. The vehicle was inspected by the dealer and the independent service center. The dealer had it for 12 days but was unable to diagnose it so I took it to an independent service center. It was also briefly looked at and listened to by the highway patrol officer who assisted me and he also thought that the transmission had failed. The check engine light was on when this incident occurred but I was having an issue with one of the glow plugs and I thought that that was the reason. The check engine light came on the night before the transmission failed.

Component/System that failed: The issue appears to originate from the transmission or drivetrain, specifically resulting in the rear wheels locking up and dragging at low speeds. It feels like something is seizing inside the drivetrain, making the truck very difficult to move. The vehicle is available for inspection upon request. How safety was put at risk: This failure presents a serious and unpredictable safety hazard. The vehicle begins locking up randomly when slowing down, such as in parking lots or residential areas. If this occurred at higher speeds or in traffic, it could easily result in a crash, loss of control, or pedestrian injury. It’s completely unreliable and unsafe to operate in this condition. Has the problem been reproduced or confirmed by a dealer or service center? The issue is part of a well-known transmission defect affecting GM’s 8-speed automatic transmissions. There are multiple class action lawsuits and thousands of consumer complaints documenting identical symptoms. GM is fully aware of the defect but has refused to issue a recall, instead allowing the time-based warranty to expire even when the mileage is still well within the 60,000-mile limit. My local GMC dealer refused to offer a loaner or goodwill repair and quoted over a week just to diagnose it despite knowing that this is a known failure point. The symptoms are consistent with the known defect GM continues to avoid addressing. Has it been inspected by the manufacturer, police, or insurance? No outside inspection has occurred yet. Given the widespread documentation of this defect and the consistency of symptoms, it should not be necessary to involve other parties. Were there any warning lamps or messages? No. There were no warning lights, messages, or alerts of any kind. The failure occurs randomly, and without any prior indication. That unpredictability makes the issue even more dangerous.

Master cylinder , less then 1000 miles was pulling out of a parking lot and the brakes went out