Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2023 GMC Sierra 2500 owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2023 GMC Sierra 2500. The contact stated while driving 45 MPH, the vehicle was losing motive power. The contact depressed the accelerator pedal; however, the vehicle failed to respond. The contact stated that the engine was revving abnormally. The contact stated that the check engine and an unknown "orange-colored" warning light illuminated. The contact pulled over and turned the vehicle off and was afraid to restart the vehicle. The contact had the vehicle towed to a local dealer where it was diagnosed and determined that a valve in the transmission needed to be replaced. The vehicle was not repaired. The manufacturer was not informed of the failure. The failure mileage was approximately 25,000.
The contact owns a 2023 GMC Sierra 2500. The contact stated while driving approximately 40 MPH, the vehicle shook abnormally twice and then switched to Low Power Mode. The contact stated there was no warning light illuminated. The contact had the vehicle towed to a local dealer, where it was diagnosed and determined that the transmission valve body needed to be replaced. The contact stated that the valve body had failed within one and a half year. The contact requested that the entire transmission be replaced. The manufacturer was informed of the failure and declined to replace the transmission. The vehicle was not repaired. The failure mileage was approximately 42,000.
The contact owns a 2023 GMC Sierra 2500. The contact stated that while driving at an undisclosed speed, the contact smelled an abnormal odor. The vehicle was taken to the dealer; however, no failure was found. The contact stated that while driving at an undisclosed speed, the contact heard an abnormal sound and smelled an abnormal odor. The vehicle was taken back to the dealer, who diagnosed the vehicle with an oil leak; however, the dealer was unable to determine the location of the leak. The manufacturer was not made aware of the failure. The failure mileage was approximately 6,000.
The valve body inside the transmission has failed and GM has known it to fail but they have done nothing about it. My vehicle has been in the shop for 2 months because of it and "parts are on back order" it's terrible i've bought this vehicle in august and it's constantly been inside the shop for various issues. My transmission lost 7th gear and it came to an immediate stop in the road because of it. tires screeching and all. truly embarrassing that you can spend 83,000$ on a truck and it be such a peice of junk.
The contact owns a 2023 GMC Sierra 2500. The contact stated that while driving approximately 35 MPH, the vehicle went into LIMP Mode, and the message "Service Transmission" was displayed. The vehicle was taken to the dealer, where it was diagnosed that the transmission valve body rod had failed. The valve body rod was replaced. It was unknown whether the vehicle was repaired. The vehicle remained at the dealer. The manufacturer was not notified of the failure. The failure mileage was approximately 44,546.
I was driving on the interstate and had just exited to refuel. As I was re-entering traffic, I accelerated to merge, and suddenly, as I was about to pull in, I felt and heard a massive metallic crash, like the entire transmission had dropped. The engine sounded abnormal, and immediately, the dashboard flashed a warning: 'Engine Power is Reduced.' The check engine light came on, and I got messages saying the transmission needed service and to schedule an appointment. I called my dealership and took it in as soon as possible. After they held the truck for a while, the service manager told me a critical part was on indefinite backorder with no fulfillment date. He handed back my keys, saying they'd reach out when it arrived. I asked if it was safe to drive, and he said yes. Later, driving from Illinois to California, my truck malfunctioned again. …
While driving the vehicle, I entered onto the interstate, as I accelerated into the flow of traffic, (approximately 45-50 mph) my truck suddenly and unexpectedly jerked and "clunked" extremely hard, I thought I had ran over a large object, approximately 5 seconds later it jerked and "popped" loudly. At that time the reduced engine power and check engine light came on causing my vehicle to suddenly slow down to 20 mph and almost being rear ended by a tractor trailer truck traveling the speed limit that had to hit his brakes e trebly hard to avoid a rear end collision. After removing my truck from the flow of traffic, I turned it off, exited the vehicle to see if I had ran over something, I did not. Cranked it up, no signs on the dash, as I started back to the travel lanes, it "surged & jerked" the reduced power and check engine light came back on. …
2023 GMC Sierra Duramax Diesel with 10 speed Allison Transmission with 28,000 miles can't be driven. Currently at the dealership due to a transmission valve body problem, codes P0700 & P0747. While driving I felt a hard shift and the truck jerk. The engine light came on and my truck went into low power mode. Let it sit over night and truck would shift fine. This happened 3 times over a 1 month period. After getting to the Chevy dealer they told me the issue is with he valve body and said they have been having multiple trucks come in with the same problem. They have a truck in there since May (4 months!) They told me there is no ETA for the part. I've read this is a common issue happening on 2023 & 2024 trucks like mine. I've read that the problems have been going on for over 1 year. This is ridiculous for a $90,000.00 truck. …
2023 GMC Sierra 2500 AT4 with approximately 36,000 miles as of current. The vehicle has experienced three valve body failures to date. GMC dealerships have completed one GM remanufactured transmission replacement and an overhaul of the second transmission. The third valve body has now failed. A GMC transmission specialist confirmed transmission failure upon recent test drive on 2/24/2025. GMC dealership refuses to perform warranty repair as they are stating "a recall is being developed" therefore will not repair/replace current defective powertrain parts. I was given the vehicle back with the verbal disclaimer "it should be safe to drive but the rear wheels can lock up at highway speed so be aware." The failure causes extreme harsh downshifting and what feels like a momentary rear wheel lock up. I have experienced this numerous times at lower speeds (<40mph). …
The contact owns a 2023 GMC Sierra 2500. The contact stated while driving 35 MPH, the vehicle gear shift was shifting independently, and the contact noticed the vehicle was shaking and the vehicle went into limp mode. The check engine lights illuminated. The contact pulled over to the right side of the road turned the vehicle off and then turned the vehicle back on and the failure persisted. The contact the gear shift was stuck in fifth gear. A dealer was contacted. The vehicle was taken to the dealer where it was diagnosed that the valve body needed to be replaced. The vehicle was not repaired. The manufacturer was notified on the failure and opened a case. The contact was referred by the manufacture to report the failure The approximate failure mileage was 50,823.
Transmission complaints in other Sierra 2500 years
Frequently asked questions
How common are transmission problems on the 2023 GMC Sierra 2500?
NHTSA has 20 complaints about the transmission & drivetrain of the 2023 GMC Sierra 2500, 61% of the model year's 33 complaints.
Is there a recall for 2023 GMC Sierra 2500 transmission problems?
No. NHTSA lists no transmission & drivetrain recall for the 2023 GMC Sierra 2500, though it has 1 recall for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2023 GMC Sierra 2500 transmission problems start?
Half of the complaints with a recorded mileage happened before about 42,000 miles, and 25% before 25,000 miles.
Is it dangerous?
Owners linked 1 crash, 0 fires and 1 injury to transmission & drivetrain problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.