GMC Sierra 2500 transmission failure problems

Filed Oct 21, 2026 · Transmission · GA

Purchased this 2022 GMC AT4 2500HD in 2022. Drove off the lot and traveled 40 miles home. Got hom,000e and pulled out of my driveway and noticed terrible bump in second gear I believe. Notified dealer and returned truck for them to replace 2 valve bodies. One week later the truck experienced terribel bumps in a downshift fashion at slow speeds, like it's downshifting from 3rd to 2nd gear. Returned truck and they replaced transmission. Problem improved some but now with 48,000 miles if your in slow speed downshifting world around 10 mph, it will lock up or hard bump that makes you think you've hit someone in front of you when you're in heavy traffic. It's been doing this at random times since new tranmission was installed. It feels like a lock-up situation. No indicators or messages show up on vehichle. I've made several compaints to dealer with no luck to this point.

Filed Oct 13, 2026 · Transmission · 107,000 miles · TX

The contact owns a 2020 GMC Sierra 2500. The contact stated that while stopped at a traffic light and making a left turn at approximately 20 MPH, the transmission failed. The vehicle was unable to exceed 10 MPH. The check engine warning light illuminated, and a dinging sound was heard following the incident. The vehicle shifted erratically, jumped gears, and made unusual noises. The contact associated the failure with the federal safety agency Campaign Number: 24V797000 (Power Train). The vehicle was towed to the dealer for diagnosis. The dealer confirmed an internal transmission failure and clutch lockup, with DTC P2732. Additionally, the transmission fluid was burnt and contained metal shavings. The dealer contacted General Motors after informing the contact of the repair costs. The failure mileage was approximately 107,000.

Filed Jul 7, 2026 · Brakes, Electrical · AK

On XXX, I was towing my camper to Copper Center, Alaska from Palmer, Alaska when my truck experienced a full transmission shut down which put the truck into "Reduced Power Mode". We descending down the road right next to Victory Bible Camp (64741 Victory Rd, Sutton-Alpine, Ak 99674) when the exhaust break turned off and the truck decreased power and the Check Engine Light illuminated. The Diagnostic that was produced by OnStar revealed 3 different codes. ( P0700 TCM, P0747 Pressure Control Solenoid A is stuck in the "ON" position, C116b faulty brake pad wear sensor.) I called GMC of Palmer and GMC OnStar advisor, both informed me that the truck needed to be towed. My safety concerns is this.... I had minimum cell phone signal and not a gas station or service station within MILES. I was on the side of the Alaska Highway 1 which is a major thoroughfare for traffic going to and from [XXX]. Thankfully there were a few kind folks that pulled over to offer assistance. My truck is a 2023 GMC Sierra 2500hd with only 26,262 Miles on it. I purchased this vehicle XXX. (It Still has the Temporary Tags on it.) If had been in a different part of Alaska when this transmission failed to function properly then we could be talking about a life or death situation. Especially, if my child was with me. I was hauling my camper that weighed ATMOST, 7,000 pounds. This is less than 40% of the trucks ability. I feel that this could put someone into a dire situation had they not had the experience with emergency situations like I have had. (Prior Military Service). I have also filed a complaint with GMC Motors. Case# XXX. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Mar 24, 2026 · Transmission · NH

While driving on the highway at normal speed, my vehicle was operating completely normally with no warning lights, messages, or prior issues. Without any warning, the vehicle suddenly lost the ability to accelerate and felt as if it had been shifted into neutral. I immediately had to pull over to the side of the highway, as this created a dangerous situation with surrounding traffic. The vehicle had to be towed to a mechanic. Upon inspection, I was informed that a coolant line connected to the transmission had completely blew off, causing a rapid loss of transmission fluid and resulting in total transmission failure. I was told this was not due to a rusted or deteriorated clamp, but rather a sudden component failure. This vehicle has been meticulously maintained and I have owned it for less than one year. There were no prior symptoms, leaks, or warning signs leading up to this incident. This appears to be a sudden and unexpected mechanical failure, not caused by neglect or misuse. The loss of power while driving at highway speed posed a serious safety risk to myself and others on the road.

Filed Mar 10, 2026 · Transmission · VA

While driving down a highway doing between 45 and 55 mph the transmission suddenly and completely faulted causing the truck to come to a complete stop. Just enough power to get to the shoulder luckily. The transmission had basically completely blown out, fluid everywhere. The insurance company did not find any comprehensive damage. The entire transmission needs to be replaced. There were no indicators showing any problems, no alerts, no warning whatsoever. Mechanics said there was a lot of metal coming out of the transmission. The truck is currently in a mechanic shop awaiting the new transmission, so at this time it is available for inspection. The safety issue here is that it happened on a busy highway, and the vehicle was no longer drivable so it needed to be towed causing more time spent on the side of the road.

Filed Oct 14, 2025 · Transmission · SC

Torque converter in my transmission we out, causing my gears to grind and lose power. Slight rumbling sound under the front passenger seat, First dealer (Palmen Motors, Kenosha WI) told me there was nothing wrong with the vehicle and no transmission error codes exist. Second dealer (Parks GMC, Greenville SC) indicated that i need a complete new transmission. Part is on backorder for the last 4 weeks and I am without my vehicle. No ETA for new part or any information on why it failed prematurely.

Filed Sep 7, 2025 · Transmission · MO

Bought a 2023 gmc sierra 2500 duramax. Went into limp mode took it to dealership the transmission was bad so they replace transmission after 3 month of dealer having my truck . Got the truck back still having issues with transmission not shifting right and the rear tires locking up at highway speeds .

Filed Aug 4, 2025 · Transmission · SC

I am receiving a "Shift to Park" warning intermittently when parking my truck. The truck is in park, but the transmission does not recognize this and flashes the warning on the dash and chimes. While this is happening, I cannot lock the vehicle, and the battery is being drained. I have read that this is a known issue with other GMC models as well. I just was given a $1074 bill to replace the transmission control with park sensor.

Filed Jun 26, 2025 · Transmission · MA

While merging into highway traffic the truck surged with RPM going to 5,000. Shortly after this event there was a grinding or rattling noise in the transmission bell housing along with unusual shifting behavior and a repeatble vibration + rotational noise between 50 and 60 MPH. The vehicle was brought to the dealer for inspection at least 4 times with claims they could not hear the obvious noise that did not go away. On the last drop off, I picked up the vehicle and the noise was gone but the shifting behavior and the constant vibration from the transmission still persists. The dealer said GMC would replace the transmission for approximately $10,000 but I would need to cover 50% of the cost. Vehicle had 35,700 miles on it and was 4 months beyond the 5yr warranty. Still unrepaired. No warning lamps, messages, or codes. Transmission component failure is imminent based on the vehicle behavior

Filed May 30, 2025 · Transmission · 42,000 miles · KS

The contact owns a 2023 GMC Sierra 2500. The contact stated while driving approximately 40 MPH, the vehicle shook abnormally twice and then switched to Low Power Mode. The contact stated there was no warning light illuminated. The contact had the vehicle towed to a local dealer, where it was diagnosed and determined that the transmission valve body needed to be replaced. The contact stated that the valve body had failed within one and a half year. The contact requested that the entire transmission be replaced. The manufacturer was informed of the failure and declined to replace the transmission. The vehicle was not repaired. The failure mileage was approximately 42,000.