2018 GMC Sierra 1500 Power Train

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.

The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving approximately 28 - 35 MPH, the vehicle started shaking abnormally. There were no warning lights illuminated. The contact continued driving cautiously. The vehicle was taken to the dealer to be diagnosed and it was determined that the torque converter had failed and needed to be replaced. The vehicle had not been repaired. The contact stated that the torque converter had been replaced twice with the first replacement performed at approximately 27,000. The manufacturer was made aware of the failure. The manufacturer had referred the contact to the NHTSA Hotline to report the failure. The failure mileage was 66,000.

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.

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.

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.

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)(6)

My 2018 gmc 1500 transmission making noise grinding. It only has 75799 Miles on it. I just was told by Laura gmc that my transmission needs replacing. I think gm should cover that. Dealer charging 7800.00 to replace it. That's not right the truck doesn't have that many miles on it. Please help

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.

At 66,963 miles my transmission failed while driving. The check engine light came on and the car would not shift out of first gear. The car was towed into Gilchrist GMC in Tacoma WA. and I was informed I needed a transmission replacement, cost of $7552.24. Come to find out there is a class action lawsuit currently filed for GM owners of this transmission, claiming some 800,000 GM products contain a knowingly faulty transmission. A recall should be in place being that nearly a million vehicles are affected by this.

I have been experiencing ongoing issues with the transmission of the vehicle I purchased in 2018. Despite it being a brand new vehicle with only 10,000 miles, I have had to bring it back to the dealer multiple times for transmission-related problems. We have tried changing the transmission fluid periodically to address the issues with shifting and shuddering, but the problem has persisted throughout my ownership.

I have a 2018 GMC Sierra 1500, it is over 5 years. So we all know our warranties are either expired and meaning out of pocket expenses will come. I mainly drive back and forth to work so my vehicle only 43,924 miles to be exact. So tell me why GM allows us to purchase a vehicle with defect oil in the transmission knowing the Torque converter will start shuttering causing some of us to purchase a new transmission and if we lucky a transmission flush. So yes I took it to the dealership causing me over $850 to have a diagnosis, computer hook up, and a transmission oil flushed and replaced. I was told this is an 45000 miles issue and it's not considered a safety issue. Personally, if I didn't know better I could had gotten rear ended and yes this should be a safety issue. Our family would like this issue addressed and be reimbursed for my expenses. Thank you!

Transmission shudder at different speeds while driving.

Transmission failure - the GM manufactured Torque converter on my truck failed to cause the transmission to fail. The internet is rife with stories of the failure of these transmissions on 2018 and 2019 GMC and Chevy Trucks.

The contact owns a 2018 GMC Sierra 1500. The contact stated while accelerating from a traffic light, the vehicle started hesitating. The contact stated no warning light was illuminated. The vehicle was not diagnosed or repaired. A dealer was not contacted. The manufacturer had not been informed of the failure. The failure mileage was approximately 99,000.

When the transmission is making changes, there is a shaking noise.

On approximately July 23, 2023, I noticed the vehicle transmission shifting hard from 1st to 2nd gear and then during the following week, this began to occur every time I drove the vehicle. There were no warning indicators appearing on the vehicle for this problem during vehicle operation. Then at higher steady speeds, the engine RPMs began to suddenly and intermittently surge slightly higher, and the steering wheel would shudder for a few moments. This began to occur more frequently and I became concerned that the transmission would catastrophically fail, causing a crash and/or personal injury. At that point I called a local dealer to make an appointment for a transmission oil change and inspection. The vehicle was taken to a local dealer on August 21, 2023 and they confirmed that there was a problem with the transmission, though at this time final diagnosis is pending. To my knowledge, the vehicle or component has not been inspected by the manufacturer, police, insurance representatives or others since I took it to the dealership on August 21, 2023.

The contact owns a 2018 GMC Sierra 1500. The contact stated that while depressing the accelerator pedal, the vehicle failed to properly accelerate. The vehicle was towed to the local dealer who diagnosed the vehicle and determined that the transmission was faulty; however, the part needed to fix the vehicle was not available. The vehicle was not repaired. The manufacturer was not yet notified of the failure. The failure mileage was 27,477.

8 speed transmission jerking, the torque convertor has been replaced 1 time already and having same issues as before. This time while in parking lot at store, was pulling into parking space, truck lundge forward during hard downshift hitting cart of person walking in front of truck. No damage and luckly barely hit the cart and not the person. I have also had the truck lunge forward when parking in my garage and hitting the garage wall in front. My truck is back at dealer again after hitting the cart in the parking lot. The 8 speed transmission issue from GM is a safety issue. My truck has already had first torque converter replaced and now having same issue with the new torque convertor

noticed ongoing vibration sounds like you are running over rumble lines on road.

The contact owns a 2018 GMC Sierra 1500. The contact stated while driving 50 MPH, the vehicle started shaking and vibrating abnormally. There was no warning light illuminated. The vehicle was taken to the dealer to be diagnosed. The contact was informed that the transmission oil needed to be flushed. The vehicle was not repaired. The manufacturer was not contacted. The failure mileage was 71,000.

Experienced heavy vibration or shudder through transmission once fluid got to around 145 degrees. Also transmission has rough shift on the first shift of a drive cycle. When I started to research I found many of the same issues reported with 8 speed transmissions. I’ve also read about the issues with the lifters not working for the active fuel management system though I haven’t experienced that yet. The replaced my transmission fluid at the dealership under the powertrain warranty. This issue showed up at around 35,000 miles, so I am very worried about the safety and reliability of this engine and transmission.

Transmission slams into gear in drive and reverse while driving it will slam into gear. And occasionally at speeds under 5 going up a hill it will have no power and struggle. I have 59000 miles on it last year around 53000 miles they did a transmission flush and that fixed it for about 9 months. Just took it back in they reprogrammed the transmission and it no longer slams In drive and reverse but still knocks back-and-forth while driving.

I have a 2018 GMC Sierra Denali. I started having problems with the 8-speed transmission at 18,000 miles. The vehicle has been to the dealership for a transmission fluid flush, a transmission relearn, a 5-week valve body replacement, two more trips to the dealership where the truck did not malfunction for them. I have had issues with an air leak on the driver side front door as well. That issue has not been resolved as well. I spent over $60,000 for the truck and have had nothing but problems. I have brought it to General Motors attention and all I would do is get a run around and no results. I was told that there is nothing more that they can do. I am beside myself and just sick as I do not know what to do. I bought a brand new vehicle in order to not have problems compared to a used one.

The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving at various speeds, the vehicle experienced shifting while shifting into a lower gear, causing the vehicle to suddenly lurch forward. The cause of the failure was not determined. The local dealer was notified of the failure but no assistance was offered. The manufacturer was not contacted. The failure mileage was 50,000.

Transmission shrudder with low mileage