General Motors has recalled 461,839 full-size trucks and SUVs with diesel engines for a transmission issue that could cause the rear wheels to lock up. The problem affects all trims of the Chevrolet Silverado and GMC Sierra from 2020 through 2022, including 1500, 2500, 3500 models. The Chevy Suburban and Tahoe, GMC Yukon, and Cadillac Escalade from 2021 are also included in the recall.
Excessive wear to a control valve in these transmissions could lead to harsh shifting. According to documents filed at the National Highway Traffic Safety Administration (NHTSA), this could lead to a condition where a harsh downshift might lock up the rear wheels. A GM engineer first reported the potential problem in June 2024 after learning about an incident involving a 2021 GMC Sierra 2500 pulling a trailer. An initial investigation by the automaker determined that potential lock-up wouldn’t be long enough to cause a loss of control, but continued analysis ultimately found otherwise.
As of mid-September, GM noted 1,888 reports of lock-ups possibly related to this issue. Among those were some reports of property damage from vehicles sliding off the road. There are three reports of minor injuries connected to lock-up, though none happened due to collisions.
The fix doesn’t involve replacing faulty valves. Instead, GM will add a software update that monitors the transmission for excessive valve wear and hard shifting. In theory, it will set a check engine light “approximately 10,000 miles” before a potential lock-up condition and limit the transmission to fifth gear. Dealer notification for the recall is already underway; specific owner notification will begin in early December.
As you might imagine, a majority of the 461,839 affected vehicles are pickup trucks. Only 1,502 Escalades fall under the recall, with 5,182 Yukons and 6,383 Suburbans/Tahoes included.
