Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2012 GMC Terrain owners, lightly cleaned up (personal details are redacted by NHTSA).
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.
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 …
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 …
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.
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!
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.
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.
I am having trouble with these things now. The powertrain especially I have not had accident yet but it keeps going dead on me in the middle of driving down road. Causing me to have to put in neutral and restart. At this time the steering goes out. This needs to be repaired before an accident does happen. The drivers seat does not move forward or backwards. The tire pressure warning does not warn until it is at 20 psi.
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! …
GMC Consumer Relations Subject: Structural Undercarriage Safety Defect - 2012 GMC Terrain SLE Vehicle Information: Year/Make/Model: 2012 GMC Terrain SLE VIN: [redacted] Mileage at Purchase: 148,305 Date of Purchase: [redacted] 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. …
Transmission complaints in other Terrain years
Frequently asked questions
How common are transmission problems on the 2012 GMC Terrain?
NHTSA has 37 complaints about the transmission & drivetrain of the 2012 GMC Terrain, 10% of the model year's 364 complaints.
Is there a recall for 2012 GMC Terrain transmission problems?
No. NHTSA lists no transmission & drivetrain recall for the 2012 GMC Terrain, though it has 4 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2012 GMC Terrain transmission problems start?
Half of the complaints with a recorded mileage happened before about 87,000 miles, and 18% before 25,000 miles.
Is it dangerous?
Owners linked 0 crashes, 2 fires and 0 injuries to transmission & drivetrain problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.