2012 GMC Terrain transmission problems

Filed Nov 16, 2025 · Electrical, Engine · MO

1. The engine suddenly lost power while driving during evening rush hour and the vehicle would no longer accelerate. 2. Because the vehicle could not maintain speed, I was unable to keep up with traffic, creating a serious safety hazard that could have resulted in a major accident. 3. The vehicle has been inspected by an independent service center for diagnosis. 4. During the incident, the “Engine Power Reduced” warning indicator illuminated just before the loss of power occurred. 5. As the vehicle slowed and came to a complete stop at an intersection, it remained unresponsive. When the traffic light turned green, the vehicle would not accelerate at all.

Filed Sep 15, 2025 · Suspension, Transmission · NY

GMC Consumer Relations Subject: Structural Undercarriage Safety Defect – 2012 GMC Terrain SLE Vehicle Information: Year/Make/Model: 2012 GMC Terrain SLE VIN: [XXX] Mileage at Purchase: 148,305 Date of Purchase: [XXX] Location: Rochester, New York I am filing a complaint regarding a severe undercarriage safety defect in my 2012 GMC Terrain SLE. The rear undercarriage of this vehicle shows heavy structural corrosion on suspension brackets and mounts. The condition produces clanging noises during normal driving, and an independent licensed mechanic has refused to work on the vehicle because the suspension integrity is unsafe. When I returned the vehicle to the dealer, I observed additional brackets being attached under the rear subframe area, suggesting reinforcement of compromised structural points. This confirms that the corrosion directly affects suspension geometry, alignment, and stability. This corrosion is not cosmetic. It is advanced structural deterioration affecting the mounting points for trailing arms and lateral links. These components are critical to safe turning, stability, and control. The corrosion compromises the ability of the suspension to keep the wheels aligned, creating serious risks of loss of control or wheel separation. What makes this more alarming is that the vehicle passed a New York State safety inspection on 07/13/2025, yet within days a mechanic refused to perform unrelated service because of the undercarriage condition. This raises questions not only about inspection validity, but also about the underlying durability and corrosion. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Apr 10, 2024 · Engine, Fuel system · MI

hello i'm writing this letter to inform you about my 2012 Terrian i have had nothing but problems with the motor and now the muffler system i have had all recalls done on this and GM is well aware of this problem i have a dealer ship to replace the timing in this motor and still uses oil and still have all the problems after the recalls have been fixed now they want me to pay over $3,000 to have new catalytic converters fixed on it now after paying $2800 for a new timing seems to me GM likes to fix the cheap stuff on these cars and make customers pay for the expensive parts must people can't afford this and junk the vehicle i will not i'm going to fight for what is right the dealer ship even told me when i took it back in to see what the code was for that GM is well aware of it and not worth putting the money into the car this is not right for customers to spend this kind of money GM needs to handle this.

Filed Mar 20, 2024 · Transmission · OH

The contact owns a 2012 GMC Terrain. The contact stated that while driving at 65 MPH, the vehicle inadvertently lost all motive power. The contact was able to pull to the shoulder of the roadway, where the vehicle was able to restart, but failure persisted. The traction control warning light was illuminated. The vehicle was towed to an independent mechanic, who was able to diagnose the failure, but the contact was unable to recall the specifics. The vehicle was repaired. The manufacturer was not notified of the failure. The failure mileage was unknown.

Filed Jan 24, 2024 · Lights, Transmission · PA · fire

My 4 cyl. AWD GMC Terrain has had excessive oil use which caused premature failure of the timing chain, loss of power/compression, blown engine, damage to exhaust manifold, cellinoids, and melted the catalytic converter. Its was a road safety, poor emissions due to failed catalytic converter. Headlights are too bright for oncoming traffic at night. Another road & safety hazard. Auto warranty is refusing to cover parts listed above caused by the timing chain and excessive oil consumption problems.

Filed Jan 16, 2024 · Transmission · WI

The contact owns a 2012 GMC Terrain. The contact stated that while driving at an undisclosed speed, the vehicle inadvertently lost motive power. The contact was able to coast the vehicle to the shoulder of the roadway, and the vehicle failed to restart. No warning lights were illuminated. The vehicle was not taken to the dealer nor an independent mechanic. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was unknown.

Filed Nov 3, 2022 · Acceleration, Engine · WA

I still have more to add to my other complaint. The fire started with alternator apparently there were crossed wires took alternator back to Orielys where I got it warrented out fixed the expanded wiring and replaced a hose and other things damaged by the little fire. Then after that things kept getting worse. Then it was spark plugs that were rusted that I replaced eventually I complained back to the dealership I got the car from and they agreed to help repair it after a posting by me on fb that I wasent a happy customer basically and that I literally had a sitting duck. Turns out the timing chain needed to be replaced and other little things. I've replaced O2 sensors camshaft sensors gaskets in catalytic converter had it inspected thinking it was a clogged exhaust the excessive oil usage was insane I would be going through 5quarts twice a month! I'm just tryna have a DECENT WORKING VEHICLE for my kids and I. I literally can't keep a job because I DONT HAVE RELIABLE transportation....I've put sooooo much money into this vehicle and now I might have a blown gasket!!! And that's because I haven't even been driving the vehicle. I got the car on Jan 7th 2021 with 129,043 miles on it as of today it has a total of 164,627 miles on it meaning in between the two years that I've owned the vehicle I have only put a total of 35,584 miles on it.....for it to have this many problems for so little mileage is INSANE!!! my kids were in the car with me today when the car started smoking like crazy from under hood and exhaust I pulled over turned the car off and took my baby off car seat in all and got away from vehicle thinking it was on fire again. I popped the hood and notice it was coming from under manifold.....meaning its probly a blown gasket after I just replaced the camshaft sensor AGAIN......it's ridiculous all the stuff thats going wrong with this vehicle with so little mileage that's been put on it.

Filed Nov 3, 2022 · Acceleration, Engine · WA · fire

First off before I got the car it had gone through a tune up. About a couple months after I got the car little things started to happen it would rock back and forth while idling I thought it was kind of an indicator that it needed oil but the percentage was still at a decent range and telling me it didn't need oil plus I hadent driven it 3000-5000 miles. Then engine light came on had it inspected codes ran came back telling me something about Throttle body So I purchased a whole new throttle body in Prosser at dealership costing me some booko buks and swapped it out when I got back home I then took it for test drive along with my 4 kids in the vehicle with me and then a little ways about 20 mins driving engine power reduced light came on along with stabilitrak and eventually lost power I was stranded in the middle of summer in the middle of nowhere with my kids windows rolled down ppl drove by and asked if I needed help and eventually came back with jumper cables tried to jump me but the car wouldn't budge I then left the car there overnight and took battery out to have it inspected the next day IT WAS FRIED (over 4 yrs old) so I had to purchase a new one costing me roughly 150 buks then took it back to where my car was stranded put it in and alarm went off and I clicked the button on key ring stuck it in ignition shit the door behind me locking keys in car while vehicle was still running and had to bust a window out to get to em. Got into car drove off made it back to my apt left it running outside while I went inside to get some stuff before I THOUGHT the problem was solved it shut off again.....I then had to replace the alternator costing me another pretty penny....about a couple weeks later I was starting a new job at a assisted living facility and arrived 10 mins early shit car off a noticed smoke coming from under hood I was confused because where the smoke was coming from couldn't have been it overheating I popped the hood and my car was on fire!!!!

Filed Jul 29, 2022 · Engine, Transmission · TX

MASSIVE OIL CONSUMPTION!! Ever si Fr the purchase of the vehicle there has been massive oil consumption leak. Taken back to the dealer for service to take care of the problem, they claim they don’t see a problem! This car has been oil leaking and also draining oil somewhere to the engine causing also power rain engine issues and also contact oil light on. Reported to GMC as well and corporate, no response! This vehicle has cut off and lost power because of oil consumption on highway with my children in the car! I have been emailing with no avail! This matter needs to be rectified immediately! It is a death trap!

Filed Dec 31, 2021 · Transmission · FL

I just spent 1,600 dollars to replace the timing chain. I know their were recalls on this, I was wondering why my vin and model were not included in these recalls?