2024 GMC Terrain: complete transmission failure

Filed Jun 23, 2026 · Transmission · GA

The vehicle has experienced a recurring transmission-related defect that has required multiple repair attempts by an authorized GMC dealership. The transmission system has also exhibited fluid leakage. Despite prior repairs, the problem has continued to reoccur. Transmission and associated transmission fluid sealing components. The vehicle is currently available for inspection upon request. A transmission is a critical safety component that transfers engine power to the wheels. A transmission defect or fluid leak can result in loss of propulsion, hesitation, inability to accelerate as expected, unexpected changes in vehicle operation, or transmission failure while driving. These conditions could increase the risk of a crash, particularly when merging into traffic, crossing intersections, or traveling at highway speeds. Transmission fluid leaking onto roadways or vehicle components may also create additional safety concerns. The vehicle has been presented to an authorized GMC dealership for diagnosis and repair on multiple occasions. The dealership has acknowledged and attempted repairs related to the transmission. The vehicle has been inspected and repaired by authorized GMC service personnel. No police involvement. No independent inspection has been performed at this time. Manufacturer-authorized dealerships have documented the repairs. Symptoms included transmission-related concerns and transmission fluid leakage. The defect first appeared while the vehicle was under warranty and has continued despite repair attempts. The recurring nature of the transmission defect and fluid leak has reduced confidence in the vehicle’s ability to operate safely and reliably. The vehicle remains under warranty and has undergone multiple repair attempts without a permanent resolution.

Filed Apr 27, 2026 · Brakes, Driver assistance · CA

This is a continuation for the federal safety agency campaign number 11711615. While an additional the federal safety agency complaint has been filed for the power train, this focuses specifically on design failures in the braking system. Our vehicle experienced a highway failure of the fuel pump, but due to the nature of a powertrain failure the car could not be put into neutral, only remain in park. The car was stranded in the middle of the road. As a AWD vehicle it similarly could not be towed as both wheels were fully locked. Tow informed us that there should be a manual release under the shifting column, however, this design safety feature had been removed in the 2024 iteration. The car was stuck on the road behind a blind turn on a somewhat busy road with vehicles typically traveling between 25-50 mph. The failure of a manual override for neutral and braking is a critical design failure that can lead to major accidents and death in the event of engine or transmission failure. There were no warnings, nor instructions or ability to get the car off the road.

Filed Feb 2, 2026 · Transmission · PA

Transmission dropped complete out of gear while driving. Got vehicle moving again. Took to dealership. Found complete internal transmission failure at 6779 miles. Transmission replaced with new unit. New transmission has erratic / hard shifts. Found replacement transmission leaking fluid due to front pump / porous case at 14800 miles. Customer Satisfaction Program N232433890 issued May 16, 2024

Filed Aug 15, 2025 · Transmission · MA

I purchased a new 2024 GMC Terrain in March 2024. At the time of the incident the mileage was approximately 18,000 miles. On [XXX], as I was driving on a MA state highway, the car lost power with no warning. I was able to "coast" into a parking lot where I contacted OnStar; a flatbed tow truck was dispatched and the car was towed to the local dealership where it was purchased. At this time, the car is still at the dealer as I was informed by dealer service consultant that it's a "massive" transmission job and parts were on back order from GMC for over three weeks. I specifically purchased this vehicle to be safe on my monthly trips to NY to visit grandchild. I no longer feel safe in this vehicle and have no guarantee this won't happen again. The fact that the transmission failed in 1 yr. old car at 18,000 miles is of great concern to me. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Sep 12, 2024 · Transmission · MD

We purchased our 2024 GMC Terrain on April 13, 2024 and on June 12, 2024 my husband and I were headed out to go to dinner and when leaving our neighborhood I noticed a weird transmission shift or slip and then the vehicle rpms increased suddenly. I pulled off the road and put the vehicle in park then I attempted to put the vehicle in reverse. The reverse lit up and just began to blink in the dash but the transmission did not go into reverse. I was able to put the vehicle in park and then drive to return home (we were less than 1/4 mile from home thankfully). Luckily we live in rural area and there were not many people on the road. Had we been on a busy road this could have been a dangerous situation. The next day the car was towed to the nearest GMC dealership. The original diagnosis was that the TCM was bad and needed to be replace and that there would be an estimated wait time of about 7 weeks. The TCM was replaced but did not resolve the issue. At that point (July 30, 2024) GM released a bulletin regarding a bad snap ring condition. The service dealer torn down the transmission and determined the snap ring was bad and they also noticed that the clutch was severely burned and needed to be replaced along with both valve bodies. By the time the parts came in and these repairs were completed, we were without the vehicle for 12 weeks. The vehicle was returned to us on 8/21/24. Unfortunately on 8/26/24 - 5 days and approximately 196 miles later, the vehicle began to behave the same way and had to be returned to the dealer. At this point we requested that GM buy the vehicle back from us which they very promptly declined. The transmission was completely tore down again and it was determined a seal or ring needed to be replaced. That repair has not worked either. Now more than 2 more weeks have passed and we are now waiting on a complete new transmission. We have again requested GM but the vehicle back from us. We are waiting on their response.

Filed Aug 20, 2024 · Transmission · MO

Purchased new from dealership 2024 GMC Terrain 4/2024. On 6/26/24 while driving the vehicle the transmission came apart and the vehicle suddenly stopped and would barely move off of the roadway. Had this happened 2 min prior while at highway speeds in crowded conditions, I can only imagine how many injuries could have occurred. My vehicle had 3800 miles on it. Upon my personal research, I found that this is a known problem with the 2024 GMC Terrains and dealerships across the country are filled with vehicles with the same problem. The dealership admitted to me that this has become "a known issue" and that they currently had 7 others with the same issue. They had my car for 8 weeks and according to my paperwork had to repair it twice as it failed the first repair road test! I filed a compaint with GM and was told "to not believe third party sites". I repeatedly asked why this wasn't a recall and they refused to answer the question. Does someone have to have their brand new transmission blow apart at 80 mph and take out others on the highway before they recall this? GM has issued multiple service bulletins to their dealerships but nothing to the public. I tried talking to the dealership and was belittled and stonewalled. Please recall these vehicles before someone is killed. I was finally given my vehicle back from the dealership today after 8 weeks because of no parts available. I am worried they repaired with the same parts that failed in the first place.I have the repair paperwork for your inspection if you would like to review it.