NHTSA Complaint #11691205 — 2021 GMC SIERRA 1500

POWER TRAIN issue reported to NHTSA

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Complaint Details

ODI Number	11691205
Vehicle	2021 GMC SIERRA 1500
Component	POWER TRAIN
Date of Incident	September 23, 2025
Date Filed	October 3, 2025
Mileage	127,000 miles
Crash	No
Fire	No
Injuries	0
Deaths	0
Vehicle Towed	No
State	ID

Consumer Description

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving 45-50 MPH, the engine revved and the transmission unintendedly downshifted, causing the vehicle to decelerate unexpectedly. The transmission then seized, and the vehicle skidded. No warning light was illuminated. The vehicle was towed to the dealer, who determined that the transmission had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 127,000.

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