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 ID: 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. *Now 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?
NHTSA complaint #11748269 — an unverified report by a vehicle owner.
I was driving north on [XXX] when I felt a slight pull to the right. I figured it was my lane assist even though I was in my lane. Seconds later it felt like if someone was in my passenger seat and just yanked my steering wheel to the right hitting the guardrail. My whole tire and the assembly was off but everything was still intact to the tire. The tie rods, axle, ball joints, the whole assembly. During investigation I was told by the mechanic that the stabilizer bar was a clean break. There was damage to the front end and all down the side. I was told by GM that the force of the impact was what ripped off my tire but it was not enough impact or damage to deploy the airbags. I was on crutches for my left leg, bruising and scar now from a huge abrasion to my right arm. Still having right shoulder pain. I sent all this to the attorney General and they tried to mediate but Afton from GM told Mike that he contacted me 3 times and I did not return her calls. I called her a left her multiple messages and she has not returned my calls. I only had the car for a few months with 5,000 miles on it. I put $2,500 down then had to turn around and get a used vehicle, put another $2,000 down and making the same payment due to the hit on my credit for a 2023 plain vehicle. Plus my insurance went up, missed work, medical bills, etc. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
NHTSA complaint #11746462 — an unverified report by a vehicle owner.
Car aggressively shakes and steering wheel shakes / jerks itself side to side when accelerating. Getting worse with time. GMC has it as a known issue but has been for months. Problem is getting worse the more it is driven. GMC says it is “safe”.
NHTSA complaint #11737213 — an unverified report by a vehicle owner.
The vehicle has been taken to the dealership at least 4 times. Each time for the same reason: when driving at 65 or higher, it sounds like it's on a flat. My screen also glitches when foot is taken off the break after a stop. The service advisor told me that there was a shortage of mechanics and asked me to bring it back next week (this is the response I have gotten each time). I have asked for a loaner twice and was told that there were none available. Therefore, I had to pay $40 to uber to work. Today, I said that I couldn't come back because it's the same issue and I have to work next week. He then let me speak to a service manager. The service manager drove it (with me in the passenger seat) and heard the sound. He noticed that it was not all of the time and that my steering wheel was a little shifty. When it was finally "fixed" (tires being rotated and some steering update), I was told to come back if I hear it again. I left at about 2pm and heard the sound again, as well as my screen began to glitch when I get off the break after a complete stop. I took a video of the glitching and took it back for both issues. I was told that some bolts were tightened and some update was done to the screen, and if I hear it again come back. On my way home at 4:35pm, the issues were not resolved.
NHTSA complaint #11707645 — an unverified report by a vehicle owner.
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)
NHTSA complaint #11687398 — an unverified report by a vehicle owner.
When driving down the interstate the vehicle sways and makes steering challenging. Potential lack of control when hitting bumps on road at highway speeds. Taken to the dealership that sold the vehicle. They confirmed the issue. No warnings lights or notifications at this time.
NHTSA complaint #11671245 — an unverified report by a vehicle owner.
While driving, the traction control light turns on. Then the gauges all start fluctuation. The dash reads service park assist. Then service stabilitrak. It does not run properly. It shifts hard. I’ve had it to the dealership twice now. The issue is still not resolved and it’s going back next Monday. I feel it will again not be resolved after reading multiple forums of others having the same issue after spending thousands of dollars. This is frightening and stressful to say the least. My car has less then sixty thousand miles on it. I should not be having this issue.
NHTSA complaint #11441264 — an unverified report by a vehicle owner.
We received a notice in the mail regarding our vehicle with our VIN #. And it mentioned our particular size engine had a recall for potential emissions part condition of degraded catalytic converter and/or oxygen sensors caused by excessive engine oil consumption affecting some vehicle from our year, make, and model. We were surprised to receive this notice because we always park in reverse and we had noticed how it was turning the curb side black coming from the tail pipe. We did receive one other notice before and took it to the dealership to have it maintenance but my honest opinion I do believe they did anything to our vehicle because it was running the same and also took it to Midas after taking it to the dealership because it ran the same. Anyhow I hope upon receiving this other notice we can actually maybe get reimbursed and actually get it fixed finally.
NHTSA complaint #11425912 — an unverified report by a vehicle owner.
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.
NHTSA complaint #11423849 — an unverified report by a vehicle owner.
I'M A SINGLE MOTHER AND MY CAR HAVE BEEN NOTHING BUT TROUBLE WHEN I'M DRIVING MY WINDSHIELD WIPERS STOP WORKING THREE TIMES I HAD TO FIX THEM MY TIRES ALWAYS NEED AIR SO EVERY WEEK I NEED MORE AIR AND THE TIRES IN THE BACK GOES OUT THE FASTEST WHY IS THIS HAPPENING ITS NOT GOOD FOR MY FAMILY PLEASE HELP
NHTSA complaint #11413381 — an unverified report by a vehicle owner.
MY CHECK ENGINE LIGHT CAME ON ALONG WITH A A MESSAGE THAT STATES 'REDUCED ENGINE POWER' AND A MESSAGE READING 'SERVICE STABILITREK WHEN I WAS DRIVING ON THE HIGHWAY AT 70 MPH. THIS CREATED SUDDENLY JERKING AND SLOW ACCELERATION SO THAT I HAD TO PULL OFF THE ROAD. I FOUND A FORUM AT [XXX] THAT REVEALS THAT THIS HAS BEEN AN ISSUE WITH GMC MODES AT LEAST AS LONG AS 2011. THE DURATION FOR WHICH THIS HAS BEEN A PROBLEM WITH GMC MODELS, AND THE FACT THAT STABILITREK IS AN INTEGRAL SAFETY FEATURE OF THE VEHICLE IN AVOIDING ACCIDENTS SEEMS TO MERIT A RECALL. PARTS OF THIS DOCUMENT HAVE BEEN REDACTED TO PROTECT PERSONALLY IDENTIFIABLE INFORMATION PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6).
NHTSA complaint #11390694 — an unverified report by a vehicle owner.
ONLY A MONTH AFTER PURCHASING MY VEHICLE I STARTED TO FEEL A WOBBLE IN THE FRONT END WHEN ACCELERATING UP HILLS AND TURNING WHILE ON THE GAS. I TOOK IT TO THE DEALER AND THEY CHANGED OUT THE FRONT TIRES STATING THAT THE PROBLEM HAD BEEN FIXED. ONCE AGAIN WHILE DRIVING THE PROBLEM PERSISTED. I TOOK THE CAR BACK TO THE DEALER AGAIN AND THEY SAID THAT THEY COULD NOT FIND ANYTHING WRONG AND SUGGESTED THAT I MAKE AN APPOINTMENT TO GO FOR A DRIVE WITH THE MECHANIC TO SHOW THEM WHAT IS HAPPENING. I MADE AN APPOINTMENT. A DAY BEFORE THE APPOINTMENT I RECEIVED A CALL FROM THE DEALERSHIP STATING THAT AN EMPLOYEE RECENTLY PURCHASED THE SAME CAR AND THEY ARE HAVING SIMILAR DIFFICULTIES. THEY FOUND ONLINE THAT GMC WAS REQUESTING INFORMATION FROM DEALERS ABOUT THE PROBLEM AND WAS TOLD THAT I NOW NEED TO WAIT FOR GMC TO COME UP WITH A SOLUTION. MY CAR SHAKES EVERY TIME THAT I DRIVE IT, IT'S AWFUL, AND IT ONLY HAS AROUND 6,000 MILES ON IT. I'M NOT SURE WHAT TO DO BECAUSE THE DEALERSHIP TOLD ME THAT I HAVE TO WAIT FOR A SOLUTION. THEY ARE NOT EVEN TRYING TO FIX ANYTHING AT THIS TIME. PLEASE HELP.
NHTSA complaint #11375056 — an unverified report by a vehicle owner.
WHEN REVERSING OUT OF A PARKING SPOT, BRAKES FAILED CAUSING ACCIDENT. MULTIPLE ATTEMPTS TO DEPRESS BRAKE PEDAL WITH NO BRAKING. HIT A PARKED CAR. AFTER SHUTTING CAR OFF AND ATTEMPTING TO MOVE VEHICLE BRAKES DID ENGAGE AND RESPOND CORRECTLY. REAR DAMAGE TO TERRAIN OCCURRED REQUIRING TOWING.
NHTSA complaint #11359950 — an unverified report by a vehicle owner.
SHOWED STABILITY TRACK. I WAS DRIVING ON THE HIGHWAY WHEN IT SHOWED SERVICE STABILITY TRAK THEN ENGINE POWER REDUCED. IT TOOK MY SPEED FROM A 65 TO 35 IN AN INSTANT CAUSING ME TO ALMOST CRASH. THEN THE CAR STARTED TO JERK AS I TRIED TO DRIVE TO FIND SOMEWHERE SAFE.
NHTSA complaint #11297053 — an unverified report by a vehicle owner.
WIPER TRANSMISSION FAILED IN A RAIN STORM WITH 70000 MILES. SAME PROBLEM AS 2013 TERRAIN. REPLACED ALL 4 TIRES AT 65000 DO TO 2 TIRES LOSING AIR SINCE NEW, WHEN THEY WERE REPLACING VALVE STEMS TWO OF THEM FELL OUT DUE TO NOT INSTALLED RITE FROM FACTORY!!
NHTSA complaint #11252127 — an unverified report by a vehicle owner.
TL* THE CONTACT OWNS A 2018 GMC TERRAIN. WHILE DRIVING 80 MPH, THE REAR PASSENGER TIRE SHOOK AND VIBRATED LOUDLY. THE CONTACT TOOK THE VEHICLE TO ED BOZARTH CHEVROLET (2001 S HAVANA ST, AURORA, CO 80014, (720) 746-2716) WHERE IT WAS DIAGNOSED THAT THE TIRES WERE FAULTY. BOTH REAR TIRES WERE REPLACED, BUT THE FAILURE CONTINUED. THE MANUFACTURER WAS NOT NOTIFIED. THE FAILURE MILEAGE WAS UNKNOWN.
NHTSA complaint #11230151 — an unverified report by a vehicle owner.