2024 GMC Sierra 1500 transmission problems

Filed Oct 26, 2026 · Electrical, Fuel system · KY

My truck has experienced recurring diagnostic trouble code P244B on [XXX], [XXX], and [XXX], 2026. The latest occurrence included a check-engine warning and reduced engine power. On [XXX], at 40,833 miles, Neil Huffman Chevrolet GMC in Frankfort, Kentucky, diagnosed a damaged diesel particulate filter differential-pressure sensor connector. The dealership's written estimate states that the connector had shorted, begun melting, and had broken wires at the back of the connector. I am concerned about the cause of the electrical overheating, the possibility of additional wiring damage, and the risk of unexpected reduced engine power while driving. I have also experienced intermittent transmission-related warnings and communication fault codes, although I do not know whether these problems are related. I understand there are GM technical bulletins addressing wiring-harness damage on certain 3.0L Duramax vehicles. I am not claiming these bulletins establish the cause of my failure, but I would appreciate having my experience evaluated for a possible safety-related defect trend. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Oct 6, 2026 · Engine, Transmission · CO

Driving at approximately 45 mph on Berthod Pass in CO, towing a snowmobile flatbed trailer, when dash display indicated "low oil pressure, Turn off Engine". By the time I could read that, the engine was already off and I was all over the road trying to find a way to get off the highway. I did not have opportunity to get off highway, and ended up against a barrier, and partially remaining in traffic. GM towed the car (not the trailer, I had to do that myself) to a dealer quite some distance from my home as opposed to the dealer where I purchased the truck. Then they told me they towed it to a different dealer. After recovering my stuff, I went to the dealer where the truck was, and they said they couldn't look at it for several days. I could not wait several days simply to find out it was going to be a couple of months before id have the truck back. I traded it in on another, larger GMC simply to get out of that engine. What I learned though, is that GM used that exchange to make about $20K. This was more the dealer, but they are part of GM. My original truck was priced below book, and not the book the public can see, but the book they say they go by. They paid me $51K on an $87K truck for trade value. Then they sold the new truck at full price, no break. I was in disaster mode, as I had a large family gathering I was preparing for at our cabin, and did not have time to fight with them. The reason for the low book trade-in value was that the value of these trucks has plummeted because of the very reasons I was replacing it, GM's failure on those engines. My original truck had about 30K miles on it when it blew. The dealer told me that the one I was replacing it with (2026 Sierra HD with 6.6L Turbo Diesel) would get similar mileage, but that was untrue. I get about half the mileage I got in the first truck, and the price of diesel is about 20% more than gas. So they found a sucker on the first truck, then that same sucker bought the second one.

Filed Sep 30, 2026 · Electrical, Transmission · MN

At approximately 2 years, 47,000 miles I received a message that I needed to service the transmission soon. I then got a message "Trailer Brakes Disabled Service Required" and another "Service Transmission Now Unable to Shift Soon". I brought the vehicle into my closest GM dealer and they said it is a faulty shift control lever. These are known to have a fault from the factory, but since I am outside of the 36,000 bumper to bumper, they will not cover the cost. It took about 2 months for the part to come in as it was on back order, and now they want $1000 to replace it.

Filed Sep 29, 2026 · Transmission · 74,200 miles · IN

The contact owns a 2024 GMC Sierra 1500. The contact stated that while driving 55 MPH, the message "Reduced Acceleration" was displayed and the vehicle decelerated quickly, and the contact was forced to pull over to the side of the road. The vehicle was taken to the dealer on several occasions to be diagnosed. During the first visit, the dealer stated that a transmission error code was retrieved and was cleared before the vehicle was returned. During the second visit, the dealer stated that the engine was consuming an excessive amount of engine oil and recommended that the engine be replaced. The contact stated that the message "Reduce Acceleration - Drive with Care" was displayed, and the vehicle went into LIMP Mode. Occasionally, after shifting to drive(D), the engine revved but the vehicle failed to respond, and the vehicle was taken back to the dealer. The manufacturer was notified of the failure. The failure mileage was 74,200.

Filed Sep 27, 2026 · Transmission · FL

I purchased a 2024 GMC Sierra 1500 Denali VIN # [XXX] on XXX with approximately 18,599 miles on the vehicle. The incidents are identified below in order. 1) XXX, Vehicle engine failure while driving at high speeds, with my daughter as a witness. I Reported the incident to Elder Ford on XXX, and my sales associate told me to take it to GMC for factory warranty. XXX took the vehicle to Central Buick GMC they performed a test that found no codes and replaced the fuel Pump Module from past experiences. They let me take the vehicle home. 2) XXX Vehicle engine failure while driving at high speeds, had to get it towed to the dealer for repair. Again, they found no codes. Had it for 5 days. Made me take it home. 3) Picked it up on XXX , was driving home and the same thing happened while going 70+ mph on the interstate. Stalled again. Drove it back to the dealer and dropped it off again, same day on the XXX. 4) Again, they found no codes and made me pick it up on XXX I was driving home on XXX and the same thing happened- lost complete power while going down the road at 40+ MPH. I had to get it towed the same day back to the dealer where it currently is at. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Sep 9, 2026 · Engine, Fuel system · WA

Lifters and camshaft failure, loud clanking, & sudden power loss on the 6.2 motor are the first noticeable signs. Instantly when everything happened check engine light, cruise control, & stabilizer lights flashed. The sudden loss of power forced the vehicle to suddenly slow down forcing my camper into the truck. I was hauling a within weight standerd camper but had difficulty bringing both the truck with the camper to a safe stop. There were no early signs or signal prior to sudden cautostrophic engine failure & all service records have been completed by a GM certified service dealer.

Filed Aug 16, 2026 · Engine, Transmission · WI

I was driving north/east on [XXX] just outside of [XXX]. After accelerating to give another driver room to move out of his lane that was ending, I lost propulsion/power. The Sierra went into Neutral and told me something like "Press Start to resume". I had to immediately get off the interstate as I was rapidly losing speed. I was able to pull over to the shoulder of the interstate on the right, just before exit 2. After getting the vehicle parked, I was never able to restart the vehicle. The motor would not turn over. The display screens kept cycling between a blank display and a display that looked like the vehicle was on but the engine never turned on. When I tried to start the car, I got a message of "conditions not correct for shift". We could not even get the vehicle into Neutral. I used OnStar to get State Patrol to show up and put lights behind us for safety. OnStar should have a recording of this call. This was on Saturday XXX in the ballpark of 2:30 pm central time. I would imagine the officer also filed a report, but I did not get it. The vehicle was towed to Billion GMC in Iowa City. Billion GMC said their initial suspicion is the 6.2L motor failed / locked up on us as this is know issue that is subject of a class action lawsuit. These vehicles ARE NOT SAFE to be on the highway, someone is going to get seriously injured, please do everything you can to get these 6.2L engines off the road before someone dies. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Aug 11, 2026 · Transmission · MI

transmission shift hard and slipping. When step on gas to go faster transmission shifts really hard like going drop on ground. Sometimes wont shift at all only goes up to 69 till left off gas and then transmission will shift. Start happening with about 10000 miles on truck and GMC said this is normal. Now need a torque converter and shift module in it.

Filed Aug 10, 2026 · Engine, Fuel system · AR

Was traveling home and started losing power going up a hill on XXX. The truck was surging, the check engine light came on and an audible warning of no (low?) oil pressure. The truck shut off on a busy interstate highway and barely got onto the shoulder. The tow truck driver had to lay on the ground with part of his body in the lane of travel to place "skids" under the rear tires because there is no way to place this vehicle in neutral for a tow without a special GM tool. When I contacted Harry Robinson GMC service center in [XXX], they told me that it was no longer a safety recall because the truck had passed diagnostics and new, high viscosity oil was put in the truck XXX. The GMC app says code P0016 which is the dreaded 6.2L camshaft to crankshaft alignment that accompanies engine component failure. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Aug 5, 2026 · Engine, Transmission · IL

Ever since I bought this truck new, I noticed a lot of metal shavings and debris in the oil filter every single time I changed the oil. I took it to the dealership multiple times to have this looked into before the engine recall came out. The dealership took pictures of the metal and sent them to a General Motors engineer, but the engineer just told them it was "normal." Later on, the truck went in for the official recall inspection, passed the PICO test, and nothing was fixed. Then on August 4, 2026, I was driving on a crowded expressway right through a construction zone with absolutely no shoulder to pull over on. Out of nowhere, the truck started hesitating badly, lost power, and the engine started making a really loud knocking noise. It was barely running, and it was incredibly dangerous because there was nowhere to go and traffic was heavy. Luckily, I was able to limp the truck along just far enough to clear the construction zone and pull over safely.