Table 1 shows one common power train related problems of the 2026 GMC Terrain.
| Problem Category | Number of Problems |
|---|---|
| Power Train problems |
The contact owns a 2026 GMC Terrain. The contact stated that while attempting to depress the accelerator pedal after coming from a complete stop, the vehicle started wobbling. A dealer was contacted. The vehicle was taken to the dealer to be diagnosed; however, the diagnostic result was unknown. The vehicle was not repaired. The contact associated the failure with technical service bulletin: pit6466 (shimmy, shake or wobble when leaving a stop); however, the VIN was not included in the bulletin. The manufacturer was notified of the failure and informed the contact that there was no recall for the failure, and opened a case. The failure mileage was 5,200.
This vehicle was bought new and is a new 2026 GMC Terrain denali with less than 5,000 miles at this time. It is a continuous event and not a specific failure date, but began soon after purchasing. The specific parts are unknown. It could be tires, wheels, steering parts (cv joints, control arms etc) or possibly transmission. I took it initially to the purchasing dealership and they took it for a ride and just dismissed the problem without investigating. Several days later I called and talked to the person who sold me the SUV and was told either him or service manager or both would call me, but neither did so. They were to set up a return date. After this insulting experience I decided to take it to a Cadillac dealer that I have had great experience with in the past. They took it for a ride and did experience the problem and investigated what they thought could be causing the SUV to wobble, shimmy, or shaking sensation. This Cadillac dealer said there investigation showed nothing wrong and returned the vehicle to me and said nothing could be done unless gm gave them permission. Next I wrote to the service manager expressing my disappointment in nothing being done and my disappointment in general motors. There is a service bulletin (document pit6466). This makes four efforts on my part to get satisfaction with this 2026 GMC Terrain denali and how it is not fun to drive and there is anxiety on the safety of the vehicle when being driven. For the problem I am experiencing with this 2026 GMC Terrain denali. There is the sensation of a “wobble, shimmy, or shaking” under low to moderate acceleration when going straight or turning. It could be tires, wheels, steering parts or power train. It is difficult to tell. Sometimes the sensation is as if the wheels will fall off. This is an awful feeling and gives you the feeling the SUV is not safe and it is not fun to drive at all. * why do I have to drive a brand new expensive SUV and feel unsafe and not enjoy do so?.
The contact owns a 2026 GMC Terrain. While driving at 28 mph, the rpm became elevated to over 3,000 rpm. There was no warning light illuminated. The contact immediately pulled over and then resumed normal operation after the failure. The vehicle was taken to the dealer to be diagnosed; however, no cause for the failure was found. The contact was advised to bring the vehicle back to the dealer if the failure reoccurred. Approximately one week after the initial failure, while driving approximately 30 mph, the transmission unexpectedly downshifted to l2. There was no warning light illuminated. The contact pulled over and restarted the vehicle, and the vehicle was taken back to the dealer. A diagnostic test was performed, and the contact was informed that the transmission needed to be rebuilt. The manufacturer was notified of the failure and was provided a case number. The vehicle remained with the dealer unrepaired. The failure mileage was approximately 1,300.
The car has always had an issue where it would just get stuck in a low gear and rpms would go high. Does this every single day. But recently it also started acting like it was put into neutral for a few seconds and then back into drive.