GM Recall for Wheel Lockup on Diesel Pickups and SUVs

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General Motors (NYSE: GM) is recalling ~462,000 pickup trucks and large SUVs with diesel engines because the rear wheels can lock, increasing the risk of a crash, according to a required recall report (24V797) made public today by the National Highway Traffic Safety Administration. The huge U.S. safety defect recall covers 2020-2022 model year Chevrolet Silverado and GMC Sierra 1500, 2500 and 3500 pickups, as well as the 2021 Cadillac Escalade, GMC Yukon, Chevrolet Tahoe and Suburban.

“A transmission control valve in some of these vehicles may be susceptible to excess wear over time, resulting in a gradual loss of pressure within the valve that can cause harsh shifting. In rare cases, the rear wheels may experience a momentary lock up,” GM said. “Excessive wear within the transmission control valve body can cause a fluid leak leading to a pressure drop that causes certain valves to move unexpectedly,” GM said.

Chronology

• On June 5, 2024, a GM engineer submitted a report to GM’s Speak Up for Safety (SUFS) program based on a customer claim that the wheels on a 2021 Sierra 2500 HD pickup allegedly locked up while towing a trailer, resulting in property damage to the vehicle and trailer. GM opened a new investigation into the condition on July 16, 2024.
• GM previously investigated this condition and determined that, in some applications, excessive wear in a control valve in these transmissions was causing harsh downshifting and, in rare cases, a momentary (<150ms) lock up of the rear wheels. Prior testing and analysis indicated this lockup was not sufficient to cause a loss of vehicle control, and GM had identified no reports of accidents or injuries associated with the condition. On July 29, 2024, NHTSA notified GM that its VOQ monitoring process had identified new potentially related reports.
• GM’s investigator completed analysis of the VOQs and a comprehensive field data search on September 17, 2024, which identified 1,888 field reports alleging a “lock up” potentially related to this condition. GM received these reports between January 30, 2020 and August 2, 2024. GM also identified eleven alleged incidents potentially related to the condition, including vehicles veering off the roadway and, in some cases, incurring minor property damage. Three minor injuries were also reported, none of which were associated with a collision. GM and NHTSA also discussed a potentially related vehicle owner questionnaire(VOQ) in January 2024.
• On October 17, 2024, GM’s Safety Field Action Decision Authority (SFADA) decided to conduct a safety recall.
• Dealers will install new transmission control module software that will monitor valve performance and detect excess wear approximately 10,000miles before a wheel lock up condition could occur. Once detected, the transmission will be limited to fifth gear, preventing the possibility of a wheel lock up condition, which occurs in a downshift from eighth gear. A service engine light and reduced propulsion message will also display in the instrument panel.
• Dealers will be notified on October 24, 2024. Owner notification is estimated to begin on December 9, 2024.