Owner-reported complaints naming the powertrain system, filed with NHTSA
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Powertrain reports that are not specifically the engine or transmission — driveshafts, axles, transfer cases and differentials. Every record below is an owner-reported complaint about the 2021 GMC Terrain submitted to NHTSA — not a confirmed defect, not a recall and not a manufacturer bulletin. 8 reports on file name it.
Complaints are reports submitted by owners and drivers to NHTSA. They are not verified and do not establish that a defect exists.
Shown in the owner’s own words, exactly as filed
Automatic transmission solenoid control valve body got stuck open and ruined the whole transmission. This has been a reoccurring problem with these vehicles. Image is from a code read. Issue was confirmed by Gastorf Chevrolet, and an independent transmission shop.
The contact owns a 2021 GMC Terrain. The contact stated that the transmission was previously replaced. The contact stated that upon starting the vehicle, the check engine warning light illuminated. The failure had occurred intermittently. Additionally, the contact stated that while driving approximately 15-20 MPH and depressing the accelerator pedal, the vehicle failed to respond for approximately 1 minute. The vehicle was taken to the Nissan dealer it was purchased several times. The dealer retrieved diagnostic trouble codes: P057C and P057E, and the brake pedal position sensor was replaced twice; however, the failure persisted. The Nissan dealer took the vehicle to a GM dealer, where the cause of the failure could not be determined. The vehicle was not repaired. The contact related the failure to TSB Number: PIT5994 (Diagnostic Tip for Reduced or Low Engine Power on Acceleration). The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 78,843.
First time I had problems with my 2021 Terrain I took it to victory GMC on 9/20/24. At the it had 45,000 miles. Every time I would drive and accelerate it would shake extremely bad in the floorboard. There was also transmission fluid leaking. I picked the car up on 9/27/2024 and was advised that both front axles were replaced, which corrected the shaking and the driver side axle seal was replaced, which was where the leak was coming from. this was covered under warranty but at 45,000 miles I should not have been already having axle problems or any type of leak. I dropped my car off again on May 5, 2025. When I called them the day I made the appointment I let them know I had a service transmission message show up and then go away, I told them it’s taking longer to kick into gear when I’m on the highway, I told them it revs up past 4 1/2 RPMS at times when it had not previously done this and it just sounded like the engine is working harder. I also told them I had a check engine line come on and go off and it was code P2271 which was an oxygen sensor code. I also told them when I had the oil changed. They told me there was a slight oil cooler leak starting. All this was supposedly addressed when I dropped it off to be serviced on 5/5/25. I was called on five 625 to pick up my vehicle notifying me that they found no issues. They were unable to verify concern concerning my check engine light. They said there was no oil cooler leaking, it was just slightly seeping, so not considered a leak. And they said no transmission concern operated as designed. Fast forward to May 9, 2025… I got in my car in the morning and once again the check engine light was on. I drove it straight to GMC and had them put the reader on it. The oxygen sensor code came on. The same code I told them about on the 5th that they said was fine on the 6th. I made an appointment once again to get this check engine light looked at although the check engine light is not on at the moment again.
The contact owns a 2021 GMC Terrain. The contact stated while driving at various speeds, the transmission erroneously shifted to the neutral, causing the vehicle to decelerate. After restarting the vehicle, the vehicle operated normally. During the failure, the message " Power Reduced" was displayed. The cause of the failure was not yet determined. The local dealer was notified of the failure. The vehicle was not repaired. The manufacturer was not contacted. The failure mileage was 36,000.
When accelerating from a stop between 35-45 mph the steering wheel shakes and you feel a vibration coming from the front wheels. I thought the wheels were loose and were about to come off.
The contact owns 2021 GMC Terrain. The contact stated upon starting the vehicle and attempting to shift the vehicle to drive, the vehicle inadvertently reversed. The contact depressed the brake pedal. There were no warning lights illuminated. The contact stated that the gear shift selector was stuck in park(P) position while the instrument panel was displaying that the vehicle was in neutral. The vehicle was towed to the dealer who informed the contact that they could not replicate the failure; however, the vehicle remained under observation at the dealer. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure but did not provide any assistance. The failure mileage was unknown. The VIN was not available.
My 2021 gmc terrain with 6000 miles on odometer. When driving up hill or going around corner transmission shudders so bad that it feels like front tires are coming off. I contacted the dealer and gm and was told there is a tsb for this complaint. GM and dealer acknowledged there was a problem but they didn't have a fix or known cause of problem
When driving car starting from a red light/getting on freeway or after making turn from a stop light when accelerating between 45 and 60 car shakes when shifting. Problem is getting worse. Car only has 6000 miles on it. I reported it to local gmc dealer and I was told GM is aware of the problem and they do not have a solution. They mentioned there is a TB out for several models that customers have reported same problem
Higher-selling and older vehicles accumulate more reports. Counts are not failure rates and are not directly comparable between vehicles that sold in very different numbers.
Categories with enough reports to have a page of their own
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