Truck just made a year old and killed on me in the middle of road. They are saying I need a new engine and maybe transmission. Could not shift truck into neutral, which left me stranded on busy road. For unsafe and had me nervous. Trying to get GMC to buy me out of this vehicle. Had same problem with 6.2 liter prior to this truck. Engine and transmission was replaced. They promised if I bought new truck, I wouldn-??t have the issues and here I am again. This is terrible.

- Denham Springs, LA, USA

While driving I experienced a loss of forward momentum, and watched the RPMs go up to 3000, wording came on the dash, but I was in traffic and wasn't able to read. I was able to reach next light about 1/4 mile, and stopped. Mad a left turn and within 200 feet, same issue. I pulled over and called OnStar. Towed to dealer. Dealer put on lift right away, as it was just in for 1st service on Saturday, with 4775 miles. Dealer informed me of a bulletin out for removing transmission pan, and splitting plates to check a ball size for 6th gear, which they found during the computer diagnostic checks. They claim to have a part tomorrow, and will install soon after.

- Budd Lake, NJ, USA

DEF tank heater, diesel exhaust fluid heater has failed which causes the truck to go into a reduced speed until fixed. GM has no parts to fix the issue! at my dealer. Currently there is three or four trucks waiting on the exact same part, it puts the truck into reduced power and speed until part is replaced

- Port Huron, MI, USA

Driving on the highway vehicle installed out in the middle of the road lucky I had enough speed to rush to the median. I heard noise coming from the engine while I was coasting off the median on the median. Try to turn on the vehicle no luck.

- Pasadena , TX, USA

The vehicle was traveling over a hill, and it failed to shift gears downwards when traveling over the hill. The vehicle-??s RPM-??s shot up to 4000+ and jolted the truck forward without pressing the gas pedal. The vehicle made a loud noise and would not accelerate in the middle of the road. The vehicle would only accelerate after giving it minimal gas from the pedal. The truck then failed to accelerate on the entire drive to the destination and failed to enter reverse upon arriving to my destination.

- Fort Johnson, LA, USA

First time it happened was on November 28th 2024 around 8pm, turned de engine on, selected the reverse gear and stepped on the gas, the reverse gear was selected but the gear didn't worked at all. I almost hit a car that was passing on the street. I out the gear on drive and got the message "reduced acceleration". I believe that is a known issue by GM's 10 speed gearbox. The car is at the dealership and they informed me by e-mail that the part transmission valve body is in a "do not sell list". I have concerns about safety because losing power on a 70miles per hour road can be dangerous and not being able to reverse is also very dangerous. There are tons of posts about it in Facebook.

- Bettendorf, IA, USA

I have experienced several occurrences of unintended acceleration while operating the vehicle at low speed. Two recent examples; 1) the truck accelerated rapidly while I was driving into my garage, and 2) the truck accelerated suddenly when pulling forward out of a parking spot in the morning shortly after starting the vehicle. In all cases, a hard application of the brake pedal slowed the vehicle. I considered whether this was operator error, possibly engaging cruise control inadvertently while turning the steering wheel, but the incident this morning does not support that potential cause. I have not spoken to the dealer about this issue.

- Houston, TX, USA

The contact owns a 2024 GMC Sierra 1500. The contact stated while driving 74 MPH, the vehicle inadvertently lost motive power, after which the vehicle was unable to accelerate above 25 MPH. The contact was able to pull over to the shoulder of the roadway and turned off the vehicle. After restarting the vehicle, the vehicle returned to normal functionality, but the failure became a regular occurrence. The check engine warning light was illuminated. The vehicle was taken to the dealer, who diagnosed a failure with the shift solenoid valve and that the serial data gateway module needed to be reprogrammed. The vehicle was not repaired. The manufacturer was notified of the failure, a case was opened, and the contact was referred to the NHTSA Hotline for assistance. The failure mileage was 24,000.

- Horn Lake, MS, USA

7500 miles and transmission valve body failed. Parts are on back order with no eta.

- Rocklin, CA, USA

The transmission would just give out. It also wouldn-??t reverse. The cause was a faulty body valve that gm can-??t produce fast enough.

- Walpole, MA, USA

On December 25, 2024, my vehicle completely stalled in the middle of the highway while travelling at 65 mph. Fortunately there were no vehicles travelling in close proximity to me at the time as my speed rapidly decreased. The abrupt stall required me to pull over to the side of the road to attempt to restart. I was unable to restart the vehicle despite numerous attempts. Jump starting was also unsuccessful. I was left stranded 90 miles away from home in freezing temperatures during a snowstorm on Christmas night. My vehicle was towed to a dealership 140 miles from home as GM would not cover the cost of towing to the dealer closest to my home (68 miles away). After numerous phone calls with GM as well as the GM dealer, I was informed 9 days later that my entire engine (6.2L V8) would need replaced. I was also informed that there are two vehicles ahead of mine that require replacement of their engines and that the engines are back-ordered. They have been unable to provide an estimated timeframe on when my vehicle will be returned to me in working condition, stating it "could be months." When I was informed of the need for an engine replacement, I placed a request for a manufacturer repurchase which was ultimately denied the following week. The agent responsible for managing my case informed me that "GMC requires two to three major failures" before they will consider a repurchase approval. The dealership was not able to provide me a loaner vehicle and I was informed that GM only reimburses $44 per day toward a rental vehicle. My occupation and location require reliable transportation in harsh winter conditions so a truck is the only reasonable option. The dealership charges $75 per day to rent a basic truck. Prior to this incident, the vehicle did not have any major issues and received routine maintenance services as recommended by the manufacturer. It was never involved in any accidents. It only had 17,553 miles and was purchased brand new in October 2023.

- Ainsworth, NE, USA

See attached document for complaint.

- Hinesville, GA, USA

On 12-26-24 the transmission on my vehicle failed suddenly going down the highway. Driving down the road a jerking motion and then all of a sudden the vehicle would not shift gears. Luckily the road wasn-??t crowed because all of a sudden the vehicle slowed and would not accelerate. If someone had been following me there was no break light indicating I was slowing down. When I returned home I discovered I didn-??t have reverse either. If I was in a place I needed to back up I couldn-??t have. I took the vehicle into the dealer the same day and they diagnosed the problem was in the transmission. They ordered the part but it isn-??t available and don-??t know when it would be available. This leads me to think there must be many other transmissions with the same problem as mine. In my case there was no accident but if it had been on a congested highway there could have been.

- Fayetteville, AR, USA

On December 13th 2024, I was unable to drive my truck in reverse. I put the truck in neutral and pushed it out of its parking spot. I was able to drive the truck to the GMC dealership for diagnosis. On December 19th, I received a call from the dealership and I was told the transmission valve body was bad. I called on January 2nd 2025 for an update on the repair and was told the valve body was on backorder and they had no ETA on the Part.

- Kingwood , WV, USA

Failed transmission; needs valve body replacement but part is on national back order. Vehicle has been at dealership since 11/12/24. Almost 2 months and no eta when part will be in. Dealership did offer loaner after first 3 weeks. Vehicle is available for inspection, no safety issues as the problem occurred in driveway at home. If the problem had happened on the highway though, there would definitely have been some safety concerns. No prior warnings or symptoms. The problem has been confirmed by the dealer and was approved as warranty work. A recall should be issued.

- Shattuck, OK, USA

The contact owns a 2024 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, the transmission shuddered. The contact stated that the shuddering was severe, causing the transmission to seize. The vehicle was taken to the dealer where the failure was identified, and the contact was informed that the transmission fluid needed to be flushed and refilled. The transmission fluid was flushed and refilled; however, the failure reoccurred. The vehicle was taken back to the dealer; however, the failure was not duplicated. The vehicle was not diagnosed or repaired by an independent mechanic or the dealer. Additionally, the contact stated that the vehicle remained at the dealer for three weeks and a loaner vehicle was provided; however, the vehicle experienced the same failure. The manufacturer was made aware of the failure and a case was filed. The failure mileage was approximately 4.

- South Charleston, OH, USA

Called multiple dealerships and found out there is a known problem with the valve body for the transmission in these vehicles, which mine is currently being towed today to the dealer. This is what happened to me today, I was driving with my two children on the interstate and all of a sudden I had no drive nothing so the speed reduced quickly. Well behind me there was a 18 wheeler on my back and almost ran into me because I had no more drive on my pickup. Then when it was safe to pull to the side of the road found out there is no reverse either. Making it even more unsafe to drive these vehicles. If I need my reverse to back my vehicle out of on coming traffic-??s I would not be able to do so. But this is the big kicker, this valve body for these vehicles are not being produced by gm. The multiple dealer ships that I called have said all the same thing, this is an extreme safety issue that should be recalled.

- Fort Kent, ME, USA