GMC Complaints

I own a 2018 GMC Sierra 1500 V8 5.3 liter which is at 46, 433 miles. Over the past few weeks I have noticed the transmission having difficulty shifting in first gear and lurching, and making shuddering noises, and as well making a constant ticking noise. After an experienced mechanic had put a diagnostic system onto my truck, his system diagnosed a Transmission Lifter Failure, specifically 2 out of the 8 lifters. A few days later (9-04-26) I took my truck to a certified GMC servicing business (Patriot Chevrolet of Hopkinsville KY 270-886-1207) and had a transmission servicing done. I had told the Customer Service representative Amanda Williams about the ticking and that I thought 2 lifters going bad in the transmission were the source of it. 3 hours later the servicing was done which cost $ 474.43. She did not know if the ticking had stopped or not. I started my engine to head home and the ticking was still happening. Nothing had changed. I got home, parked and have not started the engine since to minimize any further damage. I have become aware that this year, make and model has become infamous for the engine/transmission design and parts failure which has been at the center of thousands of class action lawsuits. I have owned this vehicle since inheriting it from my late father for 2 months before he developed dementia and suffered a broken hip. I have religiously had the oil changed every three months regardless of the mileage, and this is a sealed transmission which cannot be worked on by someone but a certified GMC mechanic, which wasn't a worry because the truck's manual says doesn't need to be worked on unless there seem to be problems. Which is what I did on 9-4-26, hoping that a servicing would fix the issue. During the 5 years that I have owned this truck, I never received ANY sort of notice from GMC that might've hinted at possible Transmission Failures, though GMC has been totally aware of. Sudden power loss dangerous and unfairly expensive to drivers.

I was notified my lifters in my 6.2 L V8 would need to be inspected for any defects. When I purchased my vehicle from Car Max here in Jackson, MS, I received a notification from the dashboard that the engine oil was low and to add oil. I turned around and took it back to the dealership as soon as possible. This happened on the first day of owner ship with in 5 minutes of driving off from the lot. I Car Max told me to just add oil and bring them the receipt and they would reimburse me. I chose not to and asked them to service the vehicle to avoid any issues with my warranty or my Car Max Shield Warranty. 2,000 miles later the same notification came across the dashboard again. I took it back to Car Max immediately and they ended up sending it off to my local GM dealership for service. They topped it off with oil after inspecting it for any leaks in the engine. None were discovered. After the 3rd notification about the engine oil level being low after close to 3,000 miles, they serviced the vehicle and put the vehicle under the Oil Consumption Watch. This took place from October 2025 through September 2026. After multiple visits, they informed me they would need to perform further test to see if the lifters were failing and that I would be responsible for the labor fees estimated at around $632.82. I informed them I have Car Max’s 150,000 mile warranty. Fidelity Insurance company informed me they would need to send an inspector out to the GM dealership. Before this takes place, they would need the vehicle to undergo various tests and I would be responsible for the labor fees. Should the engine components be found worn down. Fidelity would not cover the repairs. Should the engine components be found defective, they would cover the replacement part but not the label. Labor costs would estimate around $2,978.95. I asked the GM dealership to share this information with me in writing for documentation purposes. I asked for my vehicle to be parked until further notice.

Persistent lifter/valvetrain tapping noise, particularly around 1,500 RPM. 2022 Yukon 88,000 miles. Engine consumes more than 2 quarts of oil in between oil changes. Was told by dealer in the past that this was in normal range.

Our Yukon was taken in for the recall. Dealer did the test and said it passed and used different oil. My wife and kids were driving to [XXX] from [XXX] yesterday. As they exited the highway, the car began acting weird. Then the car completely died. It was towed due to error code P0016. Dealer said they are going to put a new engine in. I saw online that cars with replacement engines were failing too? INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

When I try to start my truck it comes up as service trailer brake control module and it has caused my truck battery to drain so I cant even crank my truck up.

1.Description of the Incident: On 6/28/26, while driving my 2023 GMC Yukon Denali at approximately 70 miles per hour with cruise control engaged, I attempted to take an exit. As I approached the exit, the vehicle’s display indicated that it was not in gear, despite being in motion. This malfunction occurred in heavy traffic, and I narrowly avoided a collision with a semi-truck as I maneuvered towards the shoulder of the road. Once safely on the shoulder, I attempted to shift the vehicle into Drive and Park, but the system reported that the application was not available, rendering the vehicle inoperable. After several unsuccessful attempts to restart the vehicle, I lost all power, leading me to suspect a battery or alternator issue. 2. Component/System Failure: The component that failed is the engine, which was subsequently diagnosed as having failed by the dealership. The failed engine is available for inspection upon request. 3. Safety Risks: This incident posed significant safety risks, including: •Risk of Collision: The sudden loss of power at high speed nearly resulted in a collision with a semi-truck and other vehicles, putting my life and the lives of others at risk. •Stranded in Dangerous Conditions: Being stranded on the side of the road in 100°F weather further exacerbated the situation, creating a potential health hazard. 4. Confirmation of the Problem: The problem was confirmed by the dealership that serviced my vehicle. They conducted a thorough inspection and determined that the engine had failed. Independent verification of the engine failure is available upon request. 5. Inspections by Authorities: The vehicle has been inspected by the dealership; however, it has not been inspected by police or insurance representatives. Documentation from the dealership regarding the inspection and engine replacement is available. 6. Warning Signs Prior to Failure: Prior to this, there were no warning lamps, messages, or symptoms indicating a problem prior.

Vehicle passed previous recall for engine defect related to complete engine failure, GM switched oil viscosity. Recall performed 10-16-25. Complete engine failure diagnosed at dealer 9-4-26, related to exact malfunction that sparked recall.

While driving my 2019 GMC Terrain with three children as passengers, the vehicle developed a braking/engine problem. The brake pedal became very hard, and the vehicle subsequently became undrivable and would not start. I received no advance warning through the GMC app indicating that the vacuum pump was failing. The vehicle was towed to a GMC dealership. The dealership diagnosed a failed vacuum pump and advised that the engine requires replacement, with an estimate of approximately $11,238. I purchased this vehicle new. I am very concerned that a vacuum-pump failure can result in reduced brake assist/increased brake-pedal effort and major engine damage without adequate advance warning. Three children were in the vehicle when this occurred, and the sudden change in braking created a serious safety concern for everyone in the vehicle. The vehicle is currently at the GMC dealership. I have requested that relevant parts be preserved and am requesting GM Policy Assistance with the repair.

The shark fin antenna has a plastic cover that is only held on by 4 plastic clips. Hi winds or car wash can compromise the cover by breaking at least two of the plastic clips allowing air to get underneath the cover and then the cover falls off. I consider this a safety issue due to the fact that if your on a highway and it comes off it can crash thru another vehicle’s windshield causing a collision with other vehicles or cause serious injury to the occupants of the vehicle it strikes. I looked online and it seems to be happening to numerous GM vehicles with it falling off.

Within the first 3 years of purchase as a new vehicle, my 2018 GMC Sierra Denali equipped with the GM 8L90 automatic transmission developed a pronounced judder during light acceleration, resembling driving over rumble strips. The condition was first reported to an authorized GMC dealer on October 23, 2021, at 26,648 miles while the powertrain warranty was in effect. GM authorized a transmission-fluid exchange from the technical service bulletin (TSB) 18-NA-355, dated April 2020, but that repair did not provide a lasting correction. The condition continued, and in 2026 the authorized dealer diagnosed an “internal stator issue causing judder on light acceleration” and recommended replacement of the torque converter. We completed the repair and retained the removed converter. The defect affected the vehicle while accelerating and created concern about predictable power delivery when merging, entering traffic or crossing an intersection. Continued torque-converter malfunction can generate heat and debris, damage the transmission and potentially impair acceleration or power transfer. GM had issued technical bulletins addressing torque-converter shudder in 2018 Sierra vehicles before this truck was purchased, but there has been no recall. I request that NHTSA evaluate whether this recurring defect presents an unreasonable safety risk in GM vehicles equipped with the 8L90 transmission.