2020 GMC Sierra 1500 Transmission Problems

Which parts fail

• Automatic transmission › Torque converter
  1

Components named in complaints (automatic and manual transmissions, CVT, axles, driveshaft, 4WD/AWD).

Mileage when the problem started

• Under 25k
  526%
• 25k–50k
  211%
• 50k–75k
  211%
• 75k–100k
  737%
• 100k–150k
  316%
• 150k+
  00%

Owner reports

Selected complaints filed with NHTSA by 2020 GMC Sierra 1500 owners, lightly cleaned up (personal details are redacted by NHTSA).

The contact owns a 2020 GMC Sierra 1500. The contact stated that while his wife was driving at an undisclosed speed, the vehicle jerked violently. The driver stated that the vehicle failed to respond as intended while depressing the accelerator or brake pedal. The check engine warning light was illuminated. The driver was able to pull over to the side of the road. The vehicle stopped jerking while driving but failed to exceed 30 MPH. The driver pulled into a parking lot and parked the vehicle. The contact was made aware of the failure and went to the parking lot. The vehicle was restarted and jerked abnormally. Additionally, while shifted into reverse(R), the vehicle failed to function as intended. …

The contact owns a 2020 GMC Sierra 1500. The contact stated while accelerating from a complete stop, the vehicle lunged forward. The contact stated that the failure recurred while driving at various speeds depressing the accelerator pedal, and while decelerating to come to a complete stop. The check engine warning light was illuminated. Additionally, the contact stated that while coming to a complete stop at a traffic light, the vehicle lunged forward violently, as if the vehicle had been rear-ended. The vehicle was taken to Quality Plus Automotive, where it was diagnosed that the transmission had failed and needed to be replaced. The local dealer, Leith GMC [phone]), and other dealers were contacted and informed the contact that an estimate for the repair could not be provided because the transmission part was not available. The vehicle was repaired by Quality Plus Automotive. …

Hi, was driving Vehicle GMC 1500 Denali, vehicle Lost power, all Lites lite up on Dashboard, Vehicle Just lost power and i swerved off Road and sideswiped a Plant Holder on side of Road, damaging side passenger Rear door. I bought the truck to GMC Rvc and they said vehicle Blew Cam shaft and Lifters. I explained to them I'm very concerned for others safety in these Vehicles with the 6.2 Engine. Someone is going to get Killed or even a family. I did look up this vehicle its not listed in Recall, but this vehicle has same engine as ones in Recall. Rvc Gmc issued me a bill for repairs for the amount of $8185.20 and they stated they took 3k off invoice. I did Pay total Invoice....I'm just asking you to please look into this as this is defiantly an issue and this year should be listed on Recall as well.. Thanku for at least looking at this. …

The contact owns a 2020 GMC Sierra 1500. The contact received notification of NHTSA Campaign Number: 24V797000 (Power Train); however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The contact stated that there was a loud clanking sound underneath the vehicle while starting the vehicle. There were no warning lights illuminated. The vehicle had been taken to the dealer and was diagnosed with transmission failure. The contact stated that the transmission had been repaired twice however, the failure persisted. The vehicle was taken to the dealer again and the transmission was replaced. The dealer was contacted about the recall and confirmed that the VIN was included in the recall however, the part to do the recall repair was not yet available. …

The contact owns a 2020 GMC Sierra 1500. The contact stated that upon taking the vehicle to the dealer for a transmission fluid flush and refill, the contact was informed that the transmission was inoperable, and the vehicle could not be driven to the residence. The dealer determined that the torque converter needed to be replaced. The dealer replaced the torque converter and advised the contact to drive over 1,000 miles for the issue to self-correct. The contact stated that the vehicle continued to shudder and drive bumpy while driving after 1,000 miles. The vehicle was taken back to the dealer, where the torque converter was replaced a second time; however, the failure persisted. The dealer informed the contact that the diagnostic test results were sent to the warranty company for the transmission replacement approval. The vehicle was not yet repaired. …

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 NHTSA Hotline for assistance. …

The contact owns a 2020 GMC Sierra 2500. The contact stated that while stopped at a traffic light and making a left turn at approximately 20 MPH, the transmission failed. The vehicle was unable to exceed 10 MPH. The check engine warning light illuminated, and a dinging sound was heard following the incident. The vehicle shifted erratically, jumped gears, and made unusual noises. The contact associated the failure with NHTSA Campaign Number: 24V797000 (Power Train). The vehicle was towed to the dealer for diagnosis. The dealer confirmed an internal transmission failure and clutch lockup, with DTC P2732. Additionally, the transmission fluid was burnt and contained metal shavings. The dealer contacted General Motors after informing the contact of the repair costs. The failure mileage was approximately 107,000.

The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at various speeds, the vehicle jerked abnormally while depressing the accelerator pedal. A dealer was contacted. The vehicle was taken to the dealer, and the technician informed the contact that the failure might be related to the engine or transmission; however, the contact was informed that the vehicle needed to be inspected to determine the cause of the failure. The vehicle was not repaired. The contact stated that the failure had occurred several times. The manufacturer was notified of the failure and informed the contact to file a complaint with the NHTSA Hotline. The approximate failure mileage was 41,248.

The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving on several occasions at various speeds, the vehicle started shaking and slipped in and out of gear, with the message "Idle Transmission" displayed. The vehicle was pulled over and shifted into park(P) and then to drive(D). There was a loud banging sound coming from the rear of the vehicle. The vehicle was towed to an independent mechanic, where it was diagnosed with transmission failure. The contact was informed that the transmission needed to be repaired. The vehicle was not yet repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 80,000.

The contact owns a 2020 GMC Sierra 1500. The contact stated while driving approximately 40-60 MPH, the transmission hesitated while depressing the accelerator pedal. A dealer was contacted. The vehicle was taken to the dealer and was diagnosed with transmission control module (TCM) failure. The contact was informed that the TCM needed to be replaced. The vehicle was not repaired. The contact related the failure to NHTSA Campaign Number: 24V797000 (POWER TRAIN); however, the VIN was not included in the recall. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline to report the failure. The failure mileage was 75,200.

Related recalls

Transmission complaints in other Sierra 1500 years