Was driving along and transmission downshifted (?) wouldn't change gears. Tachometer was like a race car. Just went wild. Limped it along to a dealership. They informed us it was probably the transmission. It was determined it was indeed the transmission. They also stated that they had 7 more waiting in the service area waiting for parts to repair. Ours was to be #8. We called the dealer we bought it from, they sent a tow truck and towed it to their service area. Luckily, I wasn't out on the interstate going 70 mph as I would have been in just a few more minutes. Very scary situation as I was in 3 lanes of traffic. It was in town, so traffic wasn't moving fast. I was 2 hours into my vacation. Needless to say, that put a damper on things. Had to rent a vehicle, unpack my vehicle and repack the rental. Oh, and by the was it is a 2024 Terrain with ONLY 2400 miles!

- Scottsville, KY, USA

I was leaving work when my car had trouble accelerating from stop. The engine revved, but the gear would not engage. It happened several more times after I stopped at a light or slowed to get on the highway. It would take a minute or so to engage, and then I could drive the car, but it made it dangerous when trying to merge on to the highway or to make any turns in to traffic. It then happened two more times as I slowed to make turns until my engine light came on as I was turning on to my street. When I finally made it to my house and put it in reverse to back into my driveway, the car wouldn't move at all. I took it to the GMC dealership because it is still under warranty. The next day when I called, they told me a piston shot through the transmission housing which caused a leak of transmission fluid. There is a GM Customer Satisfaction Program release for 2024 GMC Terrains and Arcadias that all have a defect in the transmission housing, which is causing a leak of transmission fluid. I had noticed that, whenever I slowed to make a turn anywhere prior to the engine light coming on, there was some hesitation when trying to accelerate, but I thought it was the design of the transmission and engine.

- Tulsa, OK, USA

ON [XXX] my spouse was driving her new 2024 GMC Terrain in Asheville, NC. When suddenly the car stopped and when was able to maintain control and coast to a safe area. The vehicle was subsequently taken to the dealers service center GMC Asheville, NC (Harry's on the Hill). The diagnosis was determined to be a defective a transmission valve body. In discussion with the dealer service manager he indicated this is a common occurrence with the valve body. Needless to say this defect can be fatal especially during inclement weather, fast speeds, winding narrow mountains roads! As of 15 May 2024, the dealer, GMC nor the manufacturer of the valve body has not provided a replacement part for this vehicle. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- San Antonio, TX, USA