2025 GMC SIERRA 1500 Power Train Problems

The contact owns a 2025 GMC Sierra 1500. The contact stated that while driving 75 MPH with the cruise control activated, the vehicle failed to accelerate as intended while depressing the accelerator pedal, and the vehicle decelerated to 10 MPH. In addition, the vehicle came to an abrupt stop independently. The contact’s upper body almost struck the front windshield. There was no warning light illuminated. The contact stated that shortly afterwards, the vehicle resumed driving normally at 75 MPH; however, the failure reoccurred after a short distance. The vehicle failed to accelerate as intended while depressing the accelerator pedal and abruptly came to a stop. The vehicle then resumed driving normally. No warning lights were illuminated. The contact arrived at the residence, and the vehicle was towed to the dealer. The vehicle remained at the dealer awaiting a diagnostic test. The manufacturer was not made aware of the failure. The approximate failure mileage was 7,800.

Mileage: 7,800

Intermittent shudder at 25-55 mph under light throttle (rumble-strip feel); 5-6 dealer attempts failed due to non-duplication; GMC corporate (case # 82769068] refused escalation. Safety risk: Distracts from road, potential loss of control.TSB 22-NA-182 is a known issue and dealer says they can’t repair without duplication.

Transmission module went out at 20,989 miles.

The vehicle has a vibration and stuttering feel during highway driving. Cruise between 70-75 has off and on again vibration is seat, steering wheel, and center console. The issue feels more pronounced between 60-65 and exhibits more of a hum, much like a washing machine drum that is out of balance. I have had the truck at 2 different dealerships and they have insisted it was a whee balance issue. I have also had the truck balanced at Costco. None of these issues have been alleviated with wheel balance. The dealership, where the truck was purchased, refused to test the truck at highway speeds and would only drive it for a short period at speeds up to 55mph. I have also reached out to GMC customer service, and they simply regurgitated what the dealer indicated about balance and testing at 55 mph or less in town. There seems to be a number of TSBs out on this issue. Most related to torque converter issues, but none of the dealers have indicated that my truck is impacted by any of the current TSBs, even though it exhibits all the symptoms. Not sure of the safety replications, but I am disappointed in the fact that the truck has had this issue since around 1,000 miles, and it seems like the dealer service departments are just ignoring it and refusing to do a thorough evaluation of the issue unless a code triggers or until a major failure occurs

I am writing to express my extreme disappointment and serious concern regarding a critical safety failure I experienced with my 2025 GMC Sierra 1500 Denali Unlimited (VIN: [XXX] ), which I purchased brand new in April 2025 from Cavender GMC, San Antonio, TX. On Friday, [XXX], with fewer than 9,000 miles on the vehicle, I was driving on the highway at about 65 MPH, with my minor son in the vehicle when the dash suddenly displayed a Traction Control (TRC) Fault message, followed immediately by "Acceleration is Limited." The truck experienced a severe and unexpected power loss, severely restricting my ability to accelerate or maintain safe highway speeds. I was forced to pull off the road abruptly to avoid a potentially dangerous situation. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

This is the second time in 2 days!! While driving ~35MPH the truck experienced a harsh transmission shift followed by a sudden loss of acceleration and entered shutdown mode to protect the engine. The steering became stiff, all dashboard warning lights illuminated, and a message appeared on the driver display indicating a transmission issue and advising to drive with caution. This created an extremely hazardous condition for me while driving on s busy stretch of road. I pulled onto the side of the road, came to a complete stop, shifted into park, and turned off the engine. Upon restarting the vehicle, the Check Engine Light remained on, and the transmission continued to shift abnormally at low speeds, including some noticeable shuddering. My GMC application recorded the issue and reminded me to schedule service.

While driving on the highway at 70 MPH, the truck experienced a harsh transmission shift followed by a sudden loss of acceleration and entered shutdown mode to protect the engine. The steering became stiff, all dashboard warning lights illuminated, and a message appeared on the driver display indicating a transmission issue and advising to drive with caution. The RPMs surged and the truck struggled to maintain a speed of 45 MPH while the remaining at 4000 RPM. This created an extremely hazardous situation for both me and my passenger. I safely pulled into the breakdown lane, came to a complete stop, shifted into park, and turned off the engine. Upon restarting the vehicle, the Check Engine Light remained on, and the transmission continued to shift abnormally at low speeds, including noticeable shuddering.

Truck was in "Park" idling for 20 minutes when it went from Park to "Reverse" on its own. A person sitting in a dump truck saw the backup lights on my truck come on and the truck started backing towards his truck. My truck hit his truck causing damage to my left rear bumper.

The contact owns a 2025 GMC Sierra 1500. The contact stated while driving approximately 4 MPH and turning left into a parking spot, the vehicle independently accelerated. The contact stated that the brake pedal was depressed. The contact stated there was no warning light illuminated. The contact stated that the failure was intermittent, but the failure occurred while slowing down under 5 MPH and turning to the left. The contact had taken the vehicle to a local dealer; however, the failure was not duplicated. The vehicle was not repaired. The manufacturer was informed of the failure. The failure mileage was approximately 17,000.

Mileage: 17,000

Transmission is shifting rough

While on the freeway at 65mph the truck experience a hard gear shift, loss of acceleration, went into shut down, lost steering assist, and brakes became hard, lights came on the dash for transmission issue massage, as well as Check engine light. Safety became a major concern with loss of power in the mids of a flow off traffic at freeway speeds. Vehicle had to be towed.