general problems of the 2024 GMC Sierra 2500

Truck had 3 momentary rear wheel lock ups on the highway from 41 - 52 mph.

The transmission made a loud noise, resulting in a sudden decrease in speed while driving in traffic. Felt similar to being rear ended in a collision. The lights came on in my dashboard including the check engine light. Tried driving the vehicle and it would shift erraticaly rendering un-driveable. Had to be towed to my GMC dealership for service. The initial diagnosis is an issue with the "valve body". A quick search on the internet presented several other users with this issue in this model truck with this transmission. The service department also seemed to be aware of the issue. If it is so widely known, why would there not be a recall placed on these vehicles? I'm glad I had already dropped my son off at school and that I was not on a main street where I could safely pull over and wait for the aaa driver.

Upon exiting the freeway, I pressed the gas and the vehicles rpm’s went up to 4k plus on a diesel engine, no acceleration. Thought maybe there was ice and had lost traction, tried again, same thing. Then a shudder, bang and pop. The check engine light went on and informed me of limited power and acceleration. There was no acceleration. Rpm’s would go to 2000 plus just to move. Got it to the dealership and parked it. Made a service appointment. They tried to put it into reverse and it wouldn’t move.

Vehicle shudders while accelerating and a constant speed from 1000-3000 rpm. Vehicle will shudder/shake for hundreds of miles at highway speed. Vehicle shakes violently going up steep grade. Vehicle shake is so consistently random it makes passengers ill. Warranty claim denied by gm after issue was recognized by technician.

Transmission shifting - faulty shifting between 25 - 55 mph. Took truck to dealership and they state that the radiator leaked coolant into the transmission. They are replacing the transmission and radiator under warranty. Truck only has 21k miles on it. Mostly all highway.

Valve body went out and no eta when its supposed to get in the dealership.

The contact owns a 2024 Chevrolet Sierra 2500. The contact stated that while his son was driving 60-62 mph in tenth gear, the transmission unexpectedly downshifted to seventh gear. There was an abnormally loud clunking sound coming from the vehicle. There were no warning lights illuminated. The vehicle was taken to the local dealer, where it was diagnosed and determined that the valve body needed to be replaced. The vehicle was not repaired due to the parts being on backorder. The manufacturer was contacted, but no additional assistance was provided. The failure mileage was approximately 68,000.

Code p0777 – "pressure control solenoid 'b' stuck on" – reduced propulsion / reduced engine power initiated while merging onto the interstate, this code triggered a reduction in engine power, limiting my speed to 35 mph on a highway with a posted limit between 40-70 mph. Due to the limited power, I was forced to drive on the shoulder to reach the next exit and pull into a service station. I verified the code using an obd-ii reader at autozone. Subsequently, I had the truck towed approximately 1 hour and 30 minutes back home. The vehicle has been at a gm dealership since June 24th, where the faulty valve body has been confirmed. However, there is currently no estimated arrival date for the replacement part, which was ordered on the same date. To my knowledge, the part has only been diagnosed electronically and has not yet been visually inspected. The dealer plans to remove the valve body and transmission pan once the replacement part arrives. Notably, there were no prior warnings, messages, or symptoms before this issue occurred; this code and power reduction were the first indications of a problem.

Problem #1: trailer brakes failed while pulling 40' fifth wheel trailer. Was driving at about 50mph on a 55mph road and was approaching a stop light. I went to apply my truck and trailer brakes simultaneously and quickly found out I had "lost" my trailer brake. This happened another two times within the next 10 mile trip to my house. I immediately disconnected my trailer and took my truck to the shop. The GMC dealer fixed this issue, however, it is both scary and extremely dangerous to the public when something like this happens on a brand new truck. Problem #2: right around 30,000 miles I was driving (unloaded) down the road at about 35mph when I felt a hard clunk in the transmission followed by grinding noises - immediately a notice flashed on the dash stating the truck went into reduced acceleration and the check engine light came on. I brought my truck to a local GMC dealer to be serviced on June 19th and they advised me it was the allison transmission valve body. The part has been on back-order and my truck is still at the dealership sitting in the back lot with at least 4 other 2024 hd models. I called gm twice to inquire about safety recall n242454440 (covering 2020-2022 gm vehicles) and recommend that it get extended beyond 2022 since the problem with the transmission valve body has not been resolved yet. I have not heard anything back from them since that call back in June.

2024 GMC denali hd with approx. 12, 500 miles: the truck is constantly going into limp mode. Driving down the road, first it feels like the wheels lock up with a loud noise. Immediately goes into limp mode and check engine light comes on. Took it to the dealer yesterday 6/3/25 for repairs. I just spoke to my service advisor this morning where I was told it was the valve body of the transmission that needed to be replaced. However, they were on backorder and have no eta on when they will get a replacement.

Vehicle transmission locked up and brought me down to 20-30mph out of the blue at [xxx] . Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

The contact owns a 2024 GMC Sierra 2500. The contact stated that transmission fluid was leaking onto the garage floor. The contact stated that while driving at an undisclosed speed, the transmission hesitated before shifting. The contact stated that the check transmission warning light was illuminated. The vehicle was taken to a local dealer; however, the dealer was unable to diagnose the vehicle. The vehicle was not repaired. The contact had inquired if the transmission needed to be replaced, and was informed that transmissions were on a national back order. The manufacturer was not informed of the failure. The failure mileage was 8,808.

I leased this vehicle on may 17, 2024, expecting it to function as intended. Instead, within months, it suffered recurring and escalating failures that have rendered it unsafe and unusable. January 7, 2025, I brought the truck to gates GMC for routine service and reported that it had lunged forward by approximately 2 to 2. 5 feet while shifting into park. Additionally, it exhibited irregular acceleration and rough down shifting in lower gears. I also communicated the check engine light has come on and gone off on the dashboard over the past week a few times without receiving any information on the app. At this January 7th visit, gm performed recall n242435631, supposedly addressing a known battery drain defect that caused total vehicle shutdowns. On January 24, 2025, I started the truck and was immediately overwhelmed by an intense chemical odor coming through the ventilation system. January 31 – February 1, 2025 – erratic engine warning lights & diagnostic failures on January 31, 2025, at 5:28 pm, on this key cycle the check engine light illuminated but failed to register in the gm app. On the next key cycle, the warning disappeared. The following morning, February 1, 2025, at 10:26 am, the check engine light appeared on the first key cycle before disappearing on the second key cycle. The onboard diagnostics system failed to log or retain these warnings. On February 7, 2025, the vehicle suffered a complete electrical failure. No electronic function whatsoever. Roadside assistance attempted to jump-start the truck using a high-powered jump pack, but it remained inoperable. A Ford super duty and jump pack were needed to force start the truck. February 10, 2025 the truck suffered another total electrical failure and required towing to gates GMC. The app indicated the brake system, anti-lock braking system, emissions system (specifically the exhaust system), and power train requiring service. My truck is at gates GMC and was drawing 90 milliamps opposed to 40.

Experienced loss of power and inability to maintain highway speeds. The transmission shifted violently and rpms went as high as 3500. Was able to move off the highway but cars behind us had to Dodge us when it failed. There was warning message on the dash and a cel. The truck threw two codes p0700, p0747. I was able to limp to a dealer 5 miles away. This is a known TSB with gm. There is a solenoid failure in the transmission. There is 30-90 day backorder on parts as the failure is so prevalent.

2024 GMC sierra denali ultimate 3500hd equipped with duramax lp5 and allison 10 speed transmission mission. Towing cargo trailer Thursday November 21 up 4 degree incline transmission let loose banged and popped slammed to a stop almost causing accident and went to limp mode. Took to dealership in show low arizona. Was told this is common problem and it’s the valve body assembly and parts are 60-90 days out. Mind you this truck was ordered from factory and received in March of 2024. The truck has 21k miles. So now a vehicle I bought specifically for business to haul a spray trailer will be down 2-3 months with no loaner to use to operate our business.

Transmission and transfer case leaking. Masters cylinder ( brake booster) leaking.

The column shifter that is installed on all 2024 GMC Sierra 2500hds and 3500hds poses a potential safety risk to its passengers and other drivers on the road. When the column shifter of the vehicle is in the standard drive position the shifter covers part of the screen and the direct path to the radio volume control dial and infotainment home button. It has been found and replicated that attempting to interact with the infotainment screen ui and the home button/volume control dial the driver may easily accidentally bump the shifter into the neutral position. Bumping this 8000lbs+ vehicle into neutral unintentionally can be extremely dangerous to its passengers and fellow motorists especially when hauling a heavy trailer or load like heavy-duty pickup trucks are designed to do. Bumping the truck into neutral can allow the truck to lose its acceleration capabilities and degrade braking capabilities as the engine would be disconnected from the drive wheels, limiting engine braking and exhaust braking. This kind of braking is commonly used to help stop the truck with heavy trailers and loads. This problem has been commonly referred to in multiple facebook groups relating to the 2024 GMC heavy duty truck. I personally have not had it inspected by any third party as there is not much they can do to remedy the issue. I personally recommend that general motors redesign the column shifter in these trucks shortening it to come no further than the diameter of the steering wheel eliminating any interference with the infotainment system and the home button/volume dial. Gm shall replace this updated shifter free of charge in all trucks just recently built. For gm's sake, it is important that this issue is remedied ASAP as the truck just began production and there is a limited amount on the road. This is available for inspection upon request.