General Motors has initiated a recall affecting a significant number of its full-size trucks and SUVs equipped with diesel engines. This recall encompasses 461,839 vehicles, including popular models such as the Chevrolet Silverado, GMC Sierra, Chevy Suburban, Tahoe, GMC Yukon, and Cadillac Escalade, spanning the years 2020 to 2022.
The core issue lies within the transmission system. Excessive wear on a specific control valve can lead to harsh shifting, potentially culminating in a severe condition where the rear wheels lock up abruptly. This unexpected locking can occur during a harsh downshift, posing a serious safety risk, particularly when towing heavy loads.
The problem first surfaced in June 2024 when a GM engineer became aware of an incident involving a 2021 GMC Sierra 2500. Subsequent investigations by the automaker initially suggested that any potential lock-up would be brief, minimizing the risk of loss of control. However, further analysis revealed a higher risk than originally assessed.
As of mid-September, GM had recorded 1,888 reports of incidents potentially linked to this transmission issue. While some reports involved property damage from vehicles sliding off the road, fortunately, there were only three instances of minor injuries, none of which were directly caused by collisions.
To address this problem, GM will implement a software update rather than physically replacing faulty valves. This software will monitor the transmission for signs of excessive valve wear and harsh shifting. If the system detects impending issues, it will trigger a check engine light approximately 10,000 miles before a potential lock-up and limit the transmission to fifth gear.
Dealers have already been notified of the recall, and individual owners will receive official notification in early December.
Given the nature of the affected vehicles, a significant portion of the 461,839 recalled vehicles are pickup trucks. The recall includes a relatively small number of luxury SUVs, with only 1,502 Escalades, 5,182 Yukons, and 6,383 Suburbans/Tahoes affected.