The contact owns a 2020 GMC Acadia. The contact stated while driving from a complete stop and depressing the accelerator pedal, the vehicle hesitated to respond. The contact stated that the failure also occurred while driving at various speeds. Additionally, the contact stated that the vehicle experienced unintended downshifts while driving. The contact stated that the engine revved significantly without the accelerator pedal being depressed. The messages "Unable to Shift Gears" and "Service Vehicle-?? were displayed. The contact stated that the failure had been recurring while driving. The dealer was notified of the failure and an appointment was scheduled for diagnostic testing. The vehicle was not yet diagnosed or repaired. The contact related the failure to NHTSA Campaign Number: 20V668000 (Power Train); however, the VIN was not included. The manufacturer was not notified of the failure. The failure mileage was approximately 80,000.

- Odessa, TX, USA

The contact owns a 2020 GMC Acadia. The contact stated that while driving at various speeds, the vehicle was shuddering. No warning lights were illuminated. The vehicle was taken to a local dealer, where it was diagnosed that the torque converter needed to be replaced. The vehicle was repaired; however, the failure persisted. The contact stated that while starting the vehicle, and while driving at various speeds, a buzzing noise was heard coming from the engine compartment. The contact also stated that while driving at an undisclosed speed, the vehicle stalled with the anti-theft system warning light was illuminated and the vehicle lost motive power. The vehicle was able to be restarted; however, the contact stated that unknown alarm chimes were heard. Additionally, the liftgate opened independently and various other unknown warning lights illuminated, and messages were displayed. The contact stated that the vehicle lost motive power and failed to restart. The vehicle was towed back to the dealer however, the cause of the failure could not be duplicated. The vehicle was not repaired and remained at the dealer. The contact was made aware that the warranty had expired. The manufacturer was not made aware of the failure. The approximate failure mileage was 2,000.

- Knoxville, TN, USA

15000 miles and already having transmission/torque converter shutter. In the shop now. Shutters in all gears and also while in cruise control at 70-75 + mph Dangerous when car won't shift.Dealer has confirmed this issue and has performed a flush. Problem still there and very noticeable. On star has reported these warnings and dealer confirmed codes.

- Crossville, TN, USA

I started receiving an error message that driver assist is reduced drive with car at 50k miles (i have an onstar diagnostic report and phone call made that day). It shut my car down and activated the parking break. I called Onstar at that moment it happened and they found nothing wrong with the car. It continued to happened several times after and each time I took it to the dealer they were unable to diagnose the problem. One time I was told there was a bulletin on it from GM, but not for the year of my car so they were not able to make the repair. When it finally started giving me the error all the time, they finally found it was the thermostat - $1600 and GM would not cover the part under warranty because I now had over the warranty miles even though it happened and was reported prior to that point. I have several people tell me with the same vehicle they too are having the problem - and it is costing each consumer $1600. GM knows it is a problem because it is all over the internet. There should be a recall and our costs reimbursed if we have had to make the repairs on our own.

- Du Quoin, IL, USA

AUTO STOP enabled while stopped at a stop sign on an uphill incline, there is enough of a delay on restart that it lurches and jerks upon restart, cant be good for transmission and passengers. very much a nusiance.

- Longmont, CO, USA

2020 GMC Acadia. Consumer writes in regards to loss of power at low speeds and jerking with brake light illuminated.

- Middletown, OH, USA

When the vehicle is already in motion, it automatically shifts out of drive and I am left in the middle of the road unable to accelerate for a few seconds until the vehicle automatically shifts back to drive. This happens after pulling out of my gravel driveway which is a slight incline, and onto a highway. The cause is unknown.

- Hickory, KY, USA