The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle suddenly entered Limp mode without warning. The vehicle was taken to the dealer, where the computer was reflashed and the vehicle temporarily returned to normal operation; however, the failure recurred and the vehicle was returned to the dealer. The contact noticed a burnt odor coming from the engine compartment, along with engine bay cooling fans running at an unusual rate. Upon further inspection, the dealer diagnosed the failure as a defective coolant valve. The contact associated the failure with GM Special Coverage TSB N252508341; however, the VIN was not included in the coverage program. The manufacturer was notified of the failure. The failure mileage was 107,000.
2020 GMC Sierra 1500: stuck in gear or won't shift
19 of the 484 complaints about the 2020 GMC Sierra 1500 describe stuck in gear or won't shift.
- owner complaints
- 19
- of this car's complaints
- 4%
- typical mileage
- 97,000
- recalls
- 3
Stuck in gear or won't shift by model year
What owners say
Engine went into limp mode and engine is no longer good
The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle went into LIMP Mode, and several unknown warning lights were illuminated. The vehicle lost automotive power. The vehicle was taken to the dealer to be diagnosed. There was a knock coming from the engine, there was fuel injector failure, a heated oxygen sensor control module Bank 1 failure, and fuel system failure. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 134,648.
The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at 65 MPH, the DEF tank failed. The vehicle went into three phases of LIMP Mode and the vehicle unexpectedly decelerated while driving. The DEF system service message was displayed. The vehicle was taken to the local dealer, where it was diagnosed with DEF tank failure, and the tank needed to be replaced, even though the tank was full. The part was on backorder for several weeks. The contact was not provided with a loaner. The vehicle was repaired. The manufacturer was contacted and opened a case, but no additional assistance was provided. The failure mileage was approximately 70,000.
Truck broke down with a rear-wheel lockup and had the transmission replaced in June 2025. In December 2025 and February 2026, truck lost power two times and entered limp mode while on a major highway and major interstate. The problem was misdiagnosed in June 2025, diagnosed properly in December 2025, but not properly repaired, and diagnosed properly in February 2026. All three times the vehicle had this issue, two of the same exact DTCs were present. This is a safety defect, and I have lost all confidence that the vehicle is reliable enough and safe enough for myself and my family.
The contact owns a 2020 GMC Sierra 1500. The contact stated that while starting the vehicle, the engine hesitated while turning over. The vehicle started with the check engine warning light illuminated, and the DEF (Diesel Exhaust Fluid) sensor light was illuminated. The message “94 miles before vehicle enters LIMP Mode" was displayed and instructed the contact to see the Diesel Exhaust Fluid section of the Owner's Manual. The vehicle was restricted to a 65 MPH max speed. The vehicle was towed to a dealer, where it was diagnosed, and it was determined that the DEF tank pump assembly had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 121,000.
The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle unexpectedly sputtered. There was no warning light illuminated. The vehicle was taken to the dealer, where it was diagnosed with torque converter failure. The dealer determined that the torque converter needed to be replaced. The vehicle was repaired. The contact later stated that while driving at an undisclosed speed, the vehicle unexpectedly went into LIMP Mode. There was no warning light illuminated. On several occasions, the vehicle unexpectedly downshifted and lunged forward while stopped at a traffic light. There was no warning light illuminated during the failure. The dealer was contacted. The vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure and referred the contact to the federal safety agency Hotline for assistance. The failure mileage was approximately 97,000.
Transmission 10l80 stuck solenoid truck has hesitation delayed shifting. And will not shift after certain gears.
1. On 05/9/25, the exhaust emissions system malfunctioned, triggering diagnostic trouble code P2C7A (exhaust emissions system failure). This repair, the seventh attempt since June 2024, addressed the same recurring emissions issue previously involving replacements of components such as the NOx converter (02/18/25, 03/13/24) and EGR valve (02/18/25). The vehicle is available for inspection upon request. 2. The P2C7A failure risks limp mode, reducing vehicle power unexpectedly, which is hazardous on highways, especially while towing. Exhaust emissions system malfunctions release excessive pollutants, posing environmental and health risks to others. 3. Yes, the P2C7A code was confirmed by dealer during the 05/9/25 repair, following prior confirmations (e.g., 03/31/25–04/05/25. 4. The vehicle was inspected by Young Chevrolet-Cadillac during multiple repairs (e.g., 03/31/25, 05/9/25). 5. Yes, the check engine light and OnStar emissions alerts appeared prior to the 05/9/25 repair, first noted ~June 2024 (P2C7A onset). Exhaust smell and reduced fuel economy were observed intermittently. Symptoms persisted post-03/31/25 repair, leading to the 05/23/25 service.
Vehicle Stuck in gear. Dealership was delivering the car back to myself when about a mile out from my house when the vehicles made a sudden downshift and was stuck back in gear. Driver called and notified me that it was on its way back to the shop for further work
Vehicle was going in for warranty recall; however, i requested they look at the DEF system as my DEF gauge would bounce between full and empty; along with, alert me of going into LIMP mode. GM Maintenance updated the recall and noticed that the DEF tank sensor failed and required to be replaced.
The transmission is jerking and sometimes it will not shift enough to get out of others ways. Severe slippage in the transmission I have taken the truck to the shop 3 times for the same issue. Now they tell me I need a new transmission.
Service bulletins that may apply
- Condition where the transmission control valve has worn, resulting in a gradual loss of pressure within...
- This service bulletin helps diagnose/reduce possible CCND issues on Transfer Cases
- Power train
- This bulletin helps aid the tech in possible noise that may be normal or abnormal depending on the concern...
- This service bulletin provides information on Transmission Adaptive Functions and Correcting Low Mileage...
- Power train
- Condition where the transmission control valve has worn, resulting in a gradual loss of pressure within...
- This service bulletin provides information on the harmful effects of ethylene glycol in transmission fluid.
Related recalls
Power train: automatic transmission: fluid/lubricant: valves/valve body
- What is wrong
- General Motors, LLC is recalling certain 2020 Chevrolet Silverado 2500, 3500, GMC Sierra 2500, 3500, and 2020-2022 Chevrolet Silverado 1500 and GMC Sierra 1500 vehicles that may have been repaired incorrectly under recall 24V797. The transmission control valve may fail and cause the rear wheels to lock up.
- Risk
- Rear wheel lock up increases the risk of a crash.
- Remedy
- Dealers will inspect the vehicles and update the transmission control software, free of charge. Owner notification letters were mailed March 6, 2026. Owners may contact GMC customer service at 1‑800‑462‑8782 or Chevrolet customer service at 1‑800‑222‑1020. GM's number for this recall is N252516560. Vehicle Identification Numbers (VINs) involved in this recall became searchable on on February 12, 2026.
Recall number 26V083000 · Recall details
Power train: automatic transmission: fluid/lubricant: valves/valve body
- What is wrong
- General Motors, LLC (GM) is recalling certain 2020-2022 Chevrolet Silverado 1500, 2500, 3500, GMC Sierra 1500, 2500, 3500, 2021 Cadillac Escalade, Escalade ESV, Chevrolet Tahoe, Suburban, GMC Yukon, and Yukon XL vehicles equipped with diesel engines. The transmission control valve may fail and cause the rear wheels to lock-up.
- Risk
- Rear wheel lock-up can increase the risk of a crash.
- Remedy
- Dealers will install new transmission control module software, free of charge. GM will provide a special coverage program to cover the repair of transmissions that are identified by the remedy software as containing a defective control valve. Owner notification letters were mailed December 12, 2024. Owners may contact GM customer service at 1‑888‑988‑7267, Cadillac customer service at 1‑800‑458‑8006, GMC customer service at GMC 1‑800‑462‑8782 or Chevrolet customer service at 1‑800‑222‑1020. GM's number for this recall is N242454440.
Recall number 24V797000 · Recall details
Power train: driveline: driveshaft
- What is wrong
- General Motors LLC (GM) is recalling certain 2019-2020 Chevrolet Silverado 1500 and GMC Sierra 1500 and 2020 Chevrolet Silverado 2500 trucks. One of the driveshaft joints may not have been properly welded, causing the driveshaft to separate while the vehicle is moving.
- Risk
- If the driveshaft separates, there may be a loss of propulsion, increasing the risk of crash.
- Remedy
- GM will notify owners, and dealers will replace the driveshaft, free of charge. The recall is expected to begin December 2020. Owners may contact Chevrolet customer service at 1‑800‑222‑1020 or GMC customer service at 1‑888‑988‑7267. GM's number for this recall is N202314870.
Recall number 20V650000 · Recall details
Questions about the 2020 GMC Sierra 1500 won't shift
Is stuck in gear or won't shift a common problem on the 2020 GMC Sierra 1500?
19 of 484 owner complaints about the 2020 GMC Sierra 1500 (4%) mention stuck in gear or won't shift. The model year with the most reports is 2020.
Is there a recall or service bulletin for this on the 2020 GMC Sierra 1500?
There are 3 recalls and 132 service bulletins for the same area of the car. Check them below with your VIN.
Other symptoms on the 2020 GMC Sierra 1500
Engine failure 86Check engine light 85Loss of power 54Knocking 50Misfire 26Transmission failure 20Stalling 18Power steering loss 15Won't start 15Brake failure 14Warning lights 12ABS 11Fuel pump 11Harsh shifting 11Shudder 11Backup camera 10Jerking 10Oil consumption 10Ball joint 9Fire or smoke 9Hesitation 9Adaptive cruise 7Water leak 7Headlights 5
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