2023 GMC Sierra 1500: stuck in gear or won't shift

Filed Oct 11, 2026 · Engine · ND

1) Driving on highway and lost acceleration power would only go 50 mph/went into limp mode. Dealership stated VIN number had not been released into national safety recall. Replaced crank shaft valve and was told once VIN was released I would be reimbursed, to date still in dispute. 2) low oil light came on, upon checking oil was extremely low and oil had just been changed during #1’s repair. Had towed to dealership. Engine was replaced under recall. Was charged for water pump which is in dispute. 3) shortly after and well before oil change would be due, low oil light came on again. Towed back to dealership dip stick bone dry. I asked the store vehicle inside. Called for diagnosis at 5pm stated no codes no leaks found needed to investigate further. 4) 9am following day received a vm the truck had been repossessed by GM (note there is only 10K remaining on a special order 72K truck) dealership has not responded to requests to determine if the issue was fixed or request for service ticket to know what had been done. GM Financial claimed dealership told them it “was just a part under warranty” well the warranty came from the replacement engine that was under the recall…upon talking to reinstatement dept I was informed the vehicle was not fixed. I will be redeeming the vehicle but I do not think it is right to repo during a safety recall and then auction off not fixed as that is a safety issue! Once redeemed, it is also a safety issue to get from auction lot to be repaired.

Filed Sep 10, 2026 · Acceleration, Transmission · CO

Purchased above listed vehicle new in XXX. Immediately noticed a 'coolant' smell in cab. brought vehicle in for coolant smell issue on XXX and XXX. We were told that there was no issue until finally on XXX we were told the radiator needed to be replaced at OUR expense. XXX we received a letter from GMC advising the "engine coolant control valve" may fail. In XXX while driving on mountain roads (we live in [XXX]) the check engine light came on and while at 50 mph, the vehicle went into "limp mode" we lost power and speed was immediately reduced. We now know that a symptom of that valve failure is coolant smell in the cab of the car, a problem we had attempted to address with GMC from the beginning. We could have had a serious accident driving on a busy mountain road when this failure occurred. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jun 7, 2026 · Transmission · OH

The transmission control module failed. The dealer said a I a high voltage alarm signal code. This was the diagnostic inform received from the dealership service department. Primary]: MDIAG : MISC. VEHICLE DIAGNOSIS. CHECK ENGINE LIGHT ILLUMINATED AND GETTING MESSAGE FOR SERVICE TRANSMISSION, UNABLE TO SHIFT. PLEASE CHECK AND ADVISE * Repair items per diagnosis: FOUND P07B4 STORED IN SYSTEM. VERIFIED WIRING OK TO GEAR SHIFT CONTROL MODULE. SI STATES IF WIRING GOOD TO REPLACE GEAR SHIFT CONTROL MODULE AND IF CODE RESETS TO REPLACE ECM. RECOMMEND STARTING BY REPLACING GEAR SHIFT CONTROL MODULE The truck would not shift or go into gear at all. This was concerning because the transmission could have stopped shifting while I was driving myself and my children around. This warning light came on while I was driving on the highway. My vehicle has about 58,000 miles on it and is still under powertrain warranty. But the dealership is saying this repair isn’t included.

Filed Jan 27, 2026 · Engine · NY

2023 gmc sierra denali ultimate 1500 with 6.2 v8 at highway speeds 65 MPH the car lost propulsion and said it was in neutral. Car wouldn't shift back into drive. Barely made it off the highway without an accident. Car wouldn't restart. Car brought to dealership and was told it needs a new engine and I would be without my truck for a month. Car currently has 20,200 miles on it. Plus no loaner car. Gmc has terrible customer service and sells a dangerous product

Filed Jan 19, 2026 · Transmission · NY

Driving at 35 mph in traffic and the RPMs started to increase to 3500rpm and vehicle started to slow down inevitably putting me into Reduced Acceleration..limp mode. Truck would not shift into Reverse either once I could safely merge out of traffic and put into park. Very very dangerous and scary situation.

Filed Jan 3, 2026 · Transmission · WA

Driving on highway at 60mph while towing a travel trailer and the rear tires briefly locked up, the check engine light came on with an explanation mark (!) and the dash displaying a major warning. The truck went into "limp mode." Computer code read P0747. Dealer confirmed issue and replaced valve body. Truck had 22,000 miles. Appears 2023 vehicles should be added to the original recall for long-term warranty protection.

Filed Aug 2, 2025 · Engine · NJ

50000 miles. Getting a P1098 code for a cooling issue. Truck goes into limp mode without warning and will overheat.

Filed Jul 5, 2025 · Acceleration, Engine · MI

Driving on the highway under normal driving condition, my check engine light came on and said service transmission. This then put the truck into "limp mode" and I was stuck going 60mph in a 75mph zone. Dealership scanned and found that the coolant sensor control flow valve is faulty. This part is in such demand for these vehicles that it is unknown when the part will be in.

Filed May 1, 2025 · Engine, Transmission · CT

First GMC had my car 6 weeks for a problem with the coolant control valve which failed making the truck underivable. They couldn't fix it due to not being able to get the part with a national backorder. After a few weeks having the truck back I started having erratic bucking and shifting problems and once again the engine light came on and then truck went into limp mode. Felt like the truck got stuck in one gear and was dangerous to drive. I felt unsafe operating it even to limp back to the dealer. The incident with transmission happened at high speed on interstate 95. Kinda scary. They have told me they can't fix my truck for a minimum of 6-8 weeks, but I was told that would be a miracle. So service told me probably be 10-12 weeks if they can't get the parts. If they can!

Filed Mar 18, 2025 · Electrical, Transmission · GA

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)

Filed Feb 23, 2025 · Transmission · AZ

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.

Filed Feb 17, 2025 · Engine, Fuel system · TX

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 $175.00 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