Federal authorities are examining more than 1 million Ford F-150 trucks due to issues with unintended downshifting.

      The National Highway Traffic Safety Administration (NHTSA) has initiated an investigation into the 2015-2017 Ford F-150 due to at least 138 reports of unexpected transmission downshifts while driving at speed. Customers have experienced varying effects, ranging from simple deceleration and brief wheel lock-up to a loss of control linked to the downshift. Thankfully, there have been no accidents or injuries reported.

      “Such an unrequested transmission downshift could lead to sudden rapid deceleration of the vehicle,” the NHTSA stated. “Some consumer complaints also mention that the vehicle's rear wheels may temporarily lock, seize, or skid during the downshift, causing a loss of control and increasing the likelihood of a crash and injury.”

      As the federal agency has not limited the investigation to any specific variant of the F-150, NHTSA is broadly examining the issue. Given the model years involved, they are focusing on a problem with Ford’s six-speed automatic transmission, which was previously the subject of a recall for the earlier generation F-150 (2011-2013 model years) in 2019. In that instance, customers reported a comparable issue—an abrupt and unexpected downshift followed by the potential for rear wheel lock-up.

      The 2017 model year marks the introduction of the 10-speed automatic transmission that Ford developed in collaboration with General Motors. While it doesn't seem that the 10-speed is related to this specific problem, that gearbox has been associated with various unrelated issues, including wheel lock-up in other applications.

      This investigation represents an initial step toward what could lead to a recall for the 2015-2017 F-150. Regulators will need additional time to investigate the matter thoroughly and ascertain the extent of the defect, if one exists, before making any recommendations to Ford.

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