The National Highway Traffic Safety Administration’s (NHTSA) Office of Defects Investigation is looking into a complaint that alleges an issue with the 6L90 transmission used by 2016-2018 and 2021-2022 Chevrolet Express and GMC Savana cutaway models in the U.S.

A complaint filed with the NHTSA claims that impacted vehicles could experience a loss of power when shifting into drive or reverse. The complaint notes that many of the Chevrolet Express and GMC Savana models impacted are used as school buses and ambulances and says that a loss of motive power could prevent ambulances from transporting patients and could force students to leave a school bus mid-route.

After being alerted to the issue, the Office of Defects Investigation contacted General Motors. The car manufacturer then identified two production runs of valve body separator plates that were incorrectly machined. The result could be excessive wear to the plastic valve body check balls that may lead to a loss of motive power. GM says that a total of 89 vehicles impacted are ambulances while 1,961 are currently being used as school buses.

Read: Some Chevrolet Express Cutaway And GMC Savana Cutaway Vans May Catch Fire

 Feds Investigating Chevy Express And GMC Savana For Transmission Fault

The Office of Detects Investigation notes that it is currently evaluating the severity of the potential problem and to “fully assess the potential safety-related problems.” An official recall has not yet been issued.

If a recall is announced, it will not be the first one to impact Chevrolet Express Cutaway and GMC Savana Cutaway models this year. In April, approximately 150,000 models were recalled in the United States because final-stage manufacturers could leave an unused circuit’s connectors or cut wires unsealed, potentially triggering erosion if they’re exposed to moisture or contamination. Impacted Express Cutaway models were manufactured between August 12, 2022 and March 27, 2023 while Savana Cutaway models were built from May 8, 2002 to March 23, 2023.

 Feds Investigating Chevy Express And GMC Savana For Transmission Fault