Federal safety regulators have launched an investigation into nearly 1.3 million Ford F-150 pickup trucks following reports of uncommanded downshifts that may cause abrupt deceleration and temporary loss of vehicle control.

The U.S. National Highway Traffic Safety Administration (NHTSA) said it received 138 consumer complaints involving 2015 to 2017 F-150 models equipped with the six-speed automatic transmission. In several instances, the vehicles reportedly shifted suddenly into a lower gear—sometimes from sixth to first—without driver input. Some drivers said the downshift caused the rear wheels to lock or skid briefly, creating a potential safety hazard.

The preliminary evaluation will determine whether the issue warrants a safety recall. No crashes or injuries have been reported so far, but the nature of the complaints has prompted concern due to the possibility of losing control at highway speeds.

The affected trucks use Ford’s 6R80 six-speed automatic transmission, a gearbox used widely in F-150 models during those years. The 2017 Raptor, which came with a 10-speed automatic, and most 2018-and-newer models are not part of the investigation.

This isn’t the first time Ford’s six-speed transmission has drawn scrutiny. The automaker previously recalled about 1.5 million F-150s from the 2011 to 2013 model years for similar issues. In June 2024, Ford recalled an additional 668,000 trucks from the 2014 model year after identifying a software problem that caused unexpected downshifts. In those cases, the fix involved reprogramming the powertrain control module.

As the investigation proceeds, Ford could face another large-scale recall if NHTSA identifies a defect. A software-based repair would likely be the least disruptive outcome, but if hardware changes are required, the impact could be significant for both the company and F-150 owners.

The F-150 investigation comes amid a broader set of quality control challenges for Ford. The company has issued 25 recalls so far in 2025, including actions related to backup camera failures and battery state-of-charge detection in other vehicle lines such as the Explorer, Lincoln Aviator, Bronco Sport, and Maverick.