While entering the highway from a downward slop exit ramp and towing a trailer, my truck shuddered hard and briefly locked up the rear axle. It immediately went into limp mode with a message that driving speed will be reduced. It also wouldn't shift past 5th gear. When the event took place, the OBD2 generated over 20 trouble codes. My local dealer advised I could drive it to them for repair. Upon dropping it off, they now advise it's NOT safe for driving and they have no eta on the parts to repair the issue. It's now been at the dealer for a week with no update. This is a well known issue that GM refuses to repair or provide a reasonable timeframe for repair. There are countless videos such as this one that show what happens when this takes place. [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Acworth, GA, USA

With out any warning the truck stop running at stoplight an would not start back up. We could not move the truck out of the road and blocked traffic for almost 1 hour waiting for the tow truck and getting it loaded on the tow truck (truck would not go in to neutral). The truck is now at the Dealer and they are saying that the engine seized up and will need replaced.

- Gilbert, AZ, USA

purchased a 2023 GMC Denali, 1500 on January 12, 2025. after about a week, Started to hear knocking ticking noises took the truck to the dealership with 20,362 miles. dealership diagnosed that the lifters on the driver side went bad dealership replace driver side bank, picked up my truck drove it a little over 500 miles and still heard knocking ticking noises. Send it back to the dealership and dropped it off dealership told me they would keep me an update on it.Emailed called have absolutely no idea what-??s going on with my truck. The dealership did mention of a possible engine replacement. But did not confirm after many attempts. Trying to attempt to contact the dealership emails phone calls still no answer. Called General Motors. They informed me the dealership ordered a new engine for replacement. That definitely worried me and I asked for a vehicle replacement or refund General motors, declined my request. Now I am not so confident in my truck what else could go wrong since the engine is going to be replaced" What about the transmission? Could it affect it" I don-??t know> The damage was significant in order for the engine to be replaced you just don-??t replace an engine just because, there was no light indications that something was going wrong with my truck. I-??m glad I wasn-??t driving far when I was hearing these noises coming from the engine because the engine could have seized left me stranded who knows could have crashed if the engine came to abrupt stop because of the engine failure. I purchased this truck January 12, 2025. The total of time that I have had my truck since January 12 has been 15 days. today is February 6 on Friday, February 7. My truck has been in the shop literally 30 days exactly. Still no update on when it will be ready. This is so frustrating and such a big inconvenience.

- Santa Barbara , CA, USA

Valve Body. While driving the vehicle, hard shifts occurred; the vehicle check engine light came on and stayed on while the vehicle went into limp mode. I was able to link to the GMC dealer. The dealer was not and would not inspect the vehicle at that time. I was told I needed to leave or return in two for inspection. The left vehicle was inspected the next day and determined as a value body. The GMC dealer found the part in another state and has the part shipped. I installed the part, had the GMC dealer search it, and performed a recall update.

- Flagstaff, AZ, USA

Transmission Light has been on & off for a month and half. Had it at dealer twice, dealer will not confirm a problem. Truck shifts and bucks between first and second gear. Makes stopping in traffic difficult as truck will surge and jump when down shifting while stopping. Took truck to AAMCO Transmission shop. Confirmed problem, no new transmission units or rebuild parts are available for the GM 8 Speed transmission. AAMCO is replacing unit with a used one. This is a company truck also have a second truck having the same issues with half the miles of this unit. In my opinion GM is aware of the issue in that with both trucks at dealer with same issue, they just send me off with no documentation so as to not have a paper trail. Also no new units available makes me believe that GM can not keep up with warranty replacements.

- Perry, OH, USA

Driving truck at highway speed and went to pass a group of slower vehicles on my right. I increased speed to 75 mph and the engine stopped and I had no acceleration. Engine would not shift into Neutral and would not restart. I coasted off to an exit ramp and the truck stopped in the middle of it blocking traffic for about an hour. Highway Patrol was on site to help direct traffic through the intersection of the off ramp and side road. We sat for approximately an hour before a tow truck could get us out of the intersection. The truck transmission was locked tight and the tow truck had to put the back wheel on skates to move it. I had to pay $175 to this tow truck company to move me approximately 200 yards to a local restaurant where we waited for the GMC provided tow service to arrive. GMC provided tow truck would only tow to nearest dealership which was in Weimer, TX. At the time of failure there was no warning. The truck just shut down making loud wining noises since the transmission was still in gear. This was an extremely stressful event and I was worried that someone was going to strike us at highway speed from the rear. Traffic was heavy that day on [XXX] heading [XXX] towards San Antonio and most left lane speeds were 75-80 mph and bumper to bumper traffic. The GMC Dealer in Weimer was very professional and inspected the engine on Dec 2nd notifying me that is was a total failure and would need to be replaced under warranty. The dealer had a new engine in hand within a few days and the truck was repaired with two weeks. I had a couple other issues with the OnStar system and the wireless after I picked up the truck and drive it home. I returned it to the dealer and proper parts were ordered to replace a bad control module that had failed during the engine failure. It took some additional time on my own after this was replaced to get my OnStar account back up and running correctly. This truck also had "tailgate drop" issues that the dealer fixed. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMAT

- Spring, TX, USA

Complete engine failure while driving on interstate. Vehicle went into neutral. After rolling to a stop on highway. Vehicle would not go into gear. Tow was unable to put vehicle into saftey mode and had to drag vehicle onto tow bed. At dealership techs were also unable to get vehicle to turn on or go into gear. Dealer advised the engine was complete seized. This happened while traveling on the highway there was no warning or signs of something being wrong. Vehicle simply lost all power and went into neutral while traveling 70mph with 37k on the odometer.

- Bethlehem, PA, USA

Valve Body failure. Truck rear wheels lockup during failure as transmission was unable to get past 6 gear, sending truck into limp mode at highway speeds. Codes P0700 & P0747, no issues before failure. Dealership has replaced the Valve Body, but the part number model MQC part# 24065353 has not been redesigned and feel this will be a continuous issues to saftey not knowing when it will fail again.

- Fishers, IN, USA

The trucks engine completely shut down while going approximately 60 MPH while merging onto the highway. The trucks dash flashed multiple times, a ticking noise was heard, it put itself in neutral, and shut the engine off. All power was lost. I did still have brakes. Safety was a concern as there was a vehicle behind me entering the highway too. Cars to my left as well passing at highway speeds. Once I got the vehicle stopped on the shoulder of the highway it put itself in park. It would not restart. The vehicle was towed to a local GMC dealer. There were no warning lights of any kind that came on. No indication that there was a problem. A couple days later I was informed that the truck would need an entire new engine upon inspection. I was also told by the dealer that the truck had no oil at all in it. The engine consumed it internally by their evaluation.

- Akron, OH, USA

The engine failed with 15,000 miles on it. No warning lights ever came on. Had the oil changed several days prior. Lost power, but was able to drive to the dealer, but making weird noises.

- Ham Lake, MN, USA

On Wednesday December 4th 2024 at 5:45 am on my drive to work my engine shut down, truck electronically shifted into neutral, and notified me to restart my engine. After I rolled to a stop in a safe area off the main road i tried to restart my engine, with no success. I then called my local dealership to inform them of the issue, and they instructed me to call OnStar and have them setup a tow to their facility. Once the vehicle was delivered it took the dealership 24 hours to determine that the engine had locked up and a replacement was needed. It has now been almost 2 months with no update on my truck or the replacement engine.

- Dickson, TN, USA

While under light acceleration, the vehicle violently down shifts causing the rear wheels to briefly lock up around 45mph. The vehicle traction control activates on dry road way but no check engine light is displayed. The dealership claims the valve body in the transmission is to blame and has a three month back order due to several vehicles with the same failure. The safety issue could be when the rear wheels breifly lock up during wet or slippery conditions and could cause the vehicle to lose control causing a crash.

- Tariffville, CT, USA

My check engine light came on so I stopped at a dealership to have it checked out. The dealership in Louisiana said it just needed to be updated. So I made the trip to Laredo, Texas to go to work. The next day the truck went into reduced acceleration and nearly caused me to wreck on the interstate. I had the vehichle towed to the closest GMV dealership. It turns out these vehicles have a faulty engine coolant control valve. The part is on national back order with no ETA. GMC is knowingly allow their customers to operate the trucks with this part that is know to fail. I am currently stranded in South Texas and I will have to purchase a rental vehicle to get back home to Louisiana. GMC will not help me at all with this situation.

- Trout, LA, USA

Unknown, I don-??t know why are your recalls module

- Houston , TX, USA

The truck stopped in the middle of an intersection with a transmission error code stating it could no longer shift. The transmission was locked and unable shift or move.

- Oxford, MI, USA

While driving at about 70 mph, the screens in the vehicle went black and the truck had a complete loss of power. The vehicle inadvertently braked to approximately 30 mph and went into limp mode. The check engine warning light came on and the service power steering warning light, the service transmission warning light, the low tire pressure warning light, and the traction control warning light all illuminated. There were also messages displayed on the instrument panel to Service 4-WD and Reduce Acceleration and Drive with Care.-??

- Panama City, FL, USA

after driving for a few minutes when down shifting vehicle will lock gears making the rear tires slide until a loud pop. May drive fine for a few miles again then reoccurring at any speed dealer said to drive it on SAFETY CONCERN but i did. truck has been at dealer for 2 months now. but am aware of more than mine with the same problem at the same dealership located at laura buick gmc in collinsville illinois

- Annapolis, MO, USA

The contact owns a 2023 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, the vehicle started to shake abnormally with the check engine warning light illuminated. The contact stated that after arriving at a parking structure, the transmission warning light illuminated. The vehicle was towed to the local dealer where it was diagnosed with transmission failure. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 15,000.

- Los Angeles, CA, USA

Leaking Diesel fuel, Leaking oil from the rear of the transfer case, making a claunking noise at the rear suspension, My safety is at risk for a possible fire and a crash from the Leaking oil. The vehicle was diagnosed with this problems on [XXX] at Caguas Chevrolet & GMC, also called United Collection Auto. parts were ordered on that date but not arrived. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Coamo , PR, USA

The truck jolts forward when approaching a complete stop. I have to prepare for it as I decelerate 10mph to 5mph to complete stop.

- Summit , NJ, USA