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.

- Mineral Springs, AR, USA

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.

- Little Rock, AR, USA

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

- Guysville, OH, USA

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

- New Kent, VA, USA

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.

- Las Vegas, NV, USA

The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving at an undetermined speed, the vehicle was shaking while shifting gears. The contact stated while shifting from four cylinders to eight cylinders, the rear-end was shaking violently. The hood latch warning light was illuminated. The vehicle was taken to the local dealer where it was diagnosed and determined that the tires needed to be replaced. The tires were replaced three times however, the failure persisted. The manufacturer was not contacted. The failure mileage was approximately 50,000.

- Sunapee, NH, USA

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.

- Dawsonville, GA, USA

Transmission System, hard shifts and shaking causing vehicle to down shift hard and throw itself forward almost causing an accident when coming to a stop, when vehicle was taken into service they did not diagnose the vehicle for this problem, while driving vehicle shifted down so hard causing vehicle to be stuck in only 1st gear and would not shift out of 1st gear

- East Moline, IL, USA

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.

- Shippenville , PA, USA

I was stopped at a fast food drive thru and then I tried to go to the next window and the truck wouldn-??t move at all it will just rev so I put it in parked turned off the truck and turn it back on put it on drive and was able to move for like 40 ft then it did it again so I had it towed to my home

- Seagoville , TX, USA

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.

- Goshen, IN, USA

Leak detected in the engine oil cooling lines, requiring replacement.

- Denver, CO, USA

I was driving down the highway when my vehicle loss control of operation and check engine light came on. After taking it to the GMC dealership it was determined to be a bad lifter in the motor. The garage had to take the motor completely apart to repair a bent rod and cylinder in the motor. There are numerous reports and a pending class action lawsuit concerning this device in the GMC Sierra trucks and other GMC vehicles. The lifters in the cylinder of this motor are designed to switch the engine from V4 to V6 to save on gasoline. My vehicle has been repaired by the GMC garage but I've seen reports of this problem repeatedly happening in these vehicles and it causes me great concern because if there is a lot of traffic in the area I could get hit or cause an accident by not being able to operate the truck. My vehicle is available for inspection upon request. The safety of myself and others is put at risk because the sudden equipment breakdown could cause an accident. The problem was confirmed by the dealer. No other parties have inspected the vehicle. No warning lamps went off prior to this happening and the vehicle is only a 2018 and only has 36,000 miles on it.

- Albright, WV, USA

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.

- Franklinton, LA, USA

Transmission shrudder with low mileage

- Willcox, AZ, USA

During down shifting in lower gears while reducing speed, transmission makes a loud noise followed by vehicle hard lounging forward. Occurance is intermittent and unpredictable. In city traffic this has potential to cause an accident because vehicle lounges forward when speed is reduced. Vehicle has 18900 miles. Made in 2017.

- Salt Lake City, UT, USA

Vehicle violently shakes at all speeds. Dealer blamed tires, I had new tires installed, still shaking. Dealer says "no problem found, operating as designed" truck is a nuisance to drive, shaking badly

- Lapeer, MI, USA

Transmission is slamming violently during shifting, transmission fluid is dark and contaminated. Dealer says-" operating as designed, no issue found" also truck shakes and vibrates violently while driving

- Lapeer, MI, USA

Very very bad shudder vibration noticed mostly during light throttle acceleration of 30-64 mph (48-104 km/h) during steady state driving with the transmission not actively shifting gear..

- Palm Coast , FL, USA

The contact owns a 2018 GMC Sierra 1500. The contact stated that upon depressing the accelerator, the vehicle shuddered while upshifting. There was no warning light illuminated. The contact had taken the vehicle to a local dealer where they were unable to service the vehicle. The contact had also taken the vehicle to an independent mechanic who informed him that there was a TSB placed on the vehicle. He explained that the incorrect type of transmission fluid had been placed in the transmission which would cause the failure that he had experienced. The contact then called Sewell Buick GMC of Dallas (7474 Lemmon Ave, Dallas, TX 75209) where he was informed that he would be charged a diagnostic fee prior to the repair. The manufacturer was notified of the failure but offered no assistance. The vehicle was not repaired. The failure mileage was approximately 45,000.

- Dallas, TX, USA