The contact owns a 2018 GMC Sierra 1500. The contact stated that while attempting to accelerate from a stop, the vehicle failed to accelerate while depressing the accelerator pedal. No warning light was illuminated. The vehicle was taken to a local dealer and the transmission was repaired under warranty. The contact stated that a year after the repair was completed, the failure reoccurred. The vehicle was not repaired after the most recent failure. The manufacturer was made aware of the failure. The failure mileage was approximately 94,600.

- Jacksonville, TX, USA

When I first bought my 2018 GMC Sierra with the 8 speed transmission it would shift hard from first to second gear. Then at around 58,000 miles my truck also started to have a vibration coming through the steering wheel around 45-55 mph. I took it to the dealership and they changed the transmission fluid and did a software update. I am now at 80,000 miles and my truck still shifts hard from first to second gear and makes a grinding sound when accelerating sometimes. I am afraid to drive my any long distances for fear of the transmission malfunctioning. I have not been back to the dealership since my truck is no longer under warranty. So the problem has not been reconfirmed by a dealer or independent service center or inspected by the manufacturer. There have been no warning lamps or messages or other symptoms. I hope that GM is held accountable for putting a faulty 8 speed transmission in my truck.

- Roscoe, IL, USA

My starter quit at 81,000 miles. It has always been a bit weak starting, but I have never had a starter go out on a vehicle at 81,000. I have replaced it, and the rebuilt starter is better than what was ever on this vehicle. I am also having problems with the transmission shuddering, shifting rough in low gear, and sometimes it reverses fast. Repair shops won't even touch the transmission. The dealership stated they couldn't get the problem to replicate the issues even though they know there are issues with the 8 speed transmissions.

- South Bend, IN, USA

Transmission malfunctioned while driving, causing no available power to move the vehicle. Had to coast in neutral and stopped in the road. Towed the truck to the dealer and they confirmed the transmission has failed. No warning lamps present or pre-indication of failure.

- Mckinney, TX, USA

Knocking, stalling, shaking, lost of power and steering problems. Serviced transmission twice and I was advised to serve every 30000 miles!!! I owned several types of vehicles but I never heard such things before. Technician told me that apparently many GMC customers reported same problems.

- Hot Springs National Park , AR, USA

Vehicle jumps when shifting gears. When coming to a stop it jumps Forward. Hard shifting.

- Akwesasne , NY, USA

Electrical system turns off power steering while driving Dashboard lights up like a Christmas tree service track service brake stability Had this service back in 2022 August the problems have resurfaced there are no recalls have spent lots of money and still failing Spent almost a year at the dealership fast forward to years later the same problem is occurring I am running out of money

- Warren, MI, USA

When accelerating (at times) truck will shudder. Sometimes barely noticeable, sometimes violently. Was told by dealership that torque converter is going out and will be $4000 to replace but may not even fix issue. Looking online, appears that MANY (1,000-??s) people are having same issue and that there is even a class action lawsuit about this issue. But no investigation by NHSTA yet, even though I can see many many complaints of similar issues

- Mount Olive, AL, USA

Shaking when accelerating. Sometimes so extreme it feels like you have been hit by another car. Random, inconsistent, and comes out of nowhere

- Mount Olive, AL, USA

The contact owns a 2018 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, the engine temperature rose to 210 degrees and the vehicle started jerking. The contact stated that the failure also occurred while idling for a while, or while stopped at a traffic light while refueling, and before accelerating. The failure occurred once the engine temperature rose to 210 degrees. There were no warning lights illuminated. The vehicle was taken to a certified mechanic at a transmission shop who confirmed there was a failure with the transmission; however, the mechanic was unable to determine the cause of the failure. The dealer was contacted; however, the vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was 117,000.

- Pearl, MS, USA

The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving at 45 MPH, the vehicle began to shudder, and he decreased the speed. The contact drove to his residence. The next day the vehicle was driving as expected until it became hot and began to shudder again. The transmission was not shifting as designed. The contact checked underneath the vehicle but failed to locate an issue with the transmission. The rear differential was hot and burned his fingers, but medical attention was not provided. The vehicle was taken to the local dealer, where it was diagnosed that the torque converter and transmission needed to be replaced. The vehicle was not repaired. The manufacturer was contacted, but no additional assistance was provided. The failure mileage was approximately 22,000.

- Parrish, FL, USA

The contact owns a 2018 GMC Sierra 1500. The contact stated that the vehicle failed to shift into gear as needed. The vehicle was taken to the dealer, where the contact was informed that an unknown part was loose. The vehicle was repaired. Additionally, the contact stated that while driving at various speeds, there was an abnormally loud sound coming from underneath the vehicle near the transmission. The vehicle was taken to the dealer, where the contact was informed that no failure was found. The contact stated that while driving 55 MPH, the vehicle started to decelerate unintentionally. The contact stated that there was smoke coming from the brake pedal. The contact pulled over to the side of the road and allowed the vehicle to cool down however, the brakes locked up unexpectedly. The vehicle was driven to the dealer to be diagnosed. The dealer informed the contact that the braking system had failed and needed to be replaced. The vehicle was repaired; however, the failure persisted. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 72,000.

- Greenwood, MS, USA

The contact owns a 2018 GMC Sierra 1500. The contact stated while driving 70 MPH, the vehicle started shaking violently, prompting the contact to pull over to the shoulder of the roadway. The vehicle returned to normal functionality, but upon the contact continuing to drive to his destination, the failure reoccurred. The contact stated that the RPM rapidly increased and the temperature gauge began to indicate that the engine was overheating. No warning lights were illuminated. The vehicle was taken to an independent mechanic, who diagnosed a failure with the auxiliary transmission oil cooler line, resulting in damages to the transmission. The contact was informed that the transmission needed to be replaced. The vehicle was not repaired. After investigating the failure, the contact related the failure to Special Coverage Adjustment: N182188930. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was 131,000.

- Wadsworth, OH, USA

The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving on various occasions at various speeds, the check engine warning light illuminated, and the vehicle shuddered. Additionally, the drive(D) on the instrument panel started blinking. The contact stated that the engine revved, and the vehicle went into Safe Mode and the vehicle failed to accelerate as intended. The vehicle was pulled over to the side of the road and restarted. The vehicle was taken to an independent mechanic where it was diagnosed and determined that the transmission needed to be replaced. The vehicle was currently being repaired. The manufacturer was notified of the failure. The failure mileage was approximately 40,000.

- Corunna, MI, USA

Engine AFM has failed. No engine light was present at the time. A loud ticking noise was noted from the engine bay. Was taken to get diagnosed, and the AFM was replaced. The problem was then resolved. Transmission has been jerking and hard shifting through the period of owning the vehicle. No diagnosis has been made

- Sunland Park, NM, USA

The contact owns a 2018 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, the vehicle was violently shaking. While at a stop, the vehicle slammed the brake pedal, and the steering wheel was shaking. There were no warning lights illuminated. The vehicle was taken to the local dealer, where it was diagnosed that the failure was due to the transmission. The mechanic test drove the vehicle, and the vehicle was shuddering and violently shaking, and the transmission was hard shifting. The vehicle was not repaired. The manufacturer was contacted, but no assistance was provided. The failure mileage was approximately 42,000.

- Centerport, NY, USA

The contact owns a 2018 GMC Sierra 1500. The contact stated while shifted into reverse, there was a loud clunking sound coming from the vehicle and the vehicle failed to respond as intended. The contact attempted to shift to drive(D) and neutral(N) and then back to reverse(R) however, the failure persisted. The vehicle was towed to a dealer where it was diagnosed and determined that the transmission needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 92,288.

- Garland, TX, USA

Drive train:The truck suddenly lurches forward as I'm accelerating and after I've stopped. It's very scary to stop behind a vehicle and suddenly lurch forward. Thankfully, I don't stop too close to another vehicle. The truck also shudders and experiences significant delays in acceleration after coming to a stop and going again. Automatic Emergency Braking: the automatic emergency braking system spontaneously brakes as I'm driving when there is nothing in front of me. Thankfully, nobody has been following behind me when this happens yet. I had to turn the automatic braking system off in order to avoid being hit.

- Anderson, MO, USA

The contact owns a 2018 GMC Sierra 1500. The contact stated that while stationary at a stop light and attempting to depress the accelerator pedal, the vehicle hesitated while responding. The check engine warning light was illuminated. The vehicle was taken to an independent mechanic where the vehicle was diagnosed with transmission failure. The contact stated that several unknown parts were replaced. The manufacturer was not made aware of the failure. The failure mileage was unknown. The VIN was not available.

- Holly Grove, AR, USA

We purchased our 2018 GMC Sierra 1500 z71 brand new at Fairway Buick GMC in Las Vegas, NV. Pretty much off the lot we noticed some hard shifting, but over the last year/around 60,000 miles it has become progressively worse. Come to find out GM is aware of a known defect in the transmission used in this make/model and several others by GM which causes hard shifting and jerking while upshifting and down shifting primarily between 1st and 2nd gear. This malfunction has caused the vehicle to activate "limp mode" which doesn't allow the vehicle to move out of 1st gear, while driving on the road, putting the safety of the occupants and others on the road at risk. This first happened in January 2024 while we were moving and towing a 6' U-Haul trailer. Luckily we were within a few miles of our destination and made it there safely. Upon taking it to Autonation Buick GMC, we were told they had seen this issue before and the only solution would be to replace the transmission and would cost roughly $6,000-$8,000, and that's with the generous 20% discount they were willing to offer. We opted to have the transmission flushed instead and it seemed to fix the problem temporarily. Then on [XXX] while decelerating and coming to a stop light it hard shifted from 2nd to 1st then the check engine light came on and limp mode was activated. It was 110 degrees on this day in Las Vegas when my husband was driving home from work, and again by the grace of God, he was only 5 minutes from home and made it there safely. However, what if this had occurred with our two young children in the vehicle and we were no where near home? We would have been stranded in dangerous conditions potentially putting our safety as risk. This KNOWN defect in GM transmissions is 100% a safety risk and this needs to be investigated and recalled immediately. There is an ongoing class action lawsuit against GM regarding this issue and I will be looking to get involved as well. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(

- Las V, NV, USA