Federal safety investigators are conducting an engineering analysis into 1.3 million F-150s equipped with 6R80 and 10R80 transmissions.
A total of 1,270,970 Ford F-150 trucks between the 2015 and 2017 model years are now under investigation by the National Highway Traffic Safety Administration (NHTSA) for a potential transmission-related safety issue. This latest development significantly expands on an earlier, formal recall from mid-2024, covering older Model Year 2014 trucks that could shift into first gear, regardless of the truck’s speed. Now, the safety agency’s Office of Defects Investigation is moving beyond the preliminary inquiry phase, opening a formal engineering analysis into a far wider range of trucks to determine the scale of the unexpected downshifting issue.
ODI first began looking into instances of F-150 trucks’ transmissions downshifting with no warning in March 2025. According to the office’s opening report: “The [owner] complaints allege that, without warning or driver input, the subject vehicles experienced a sudden and rapid deceleration often accompanied by temporary rear wheel lockup, seizure, or skidding, resulting in a loss of vehicle control that increases the risk of crash and injury to all motorists, including those not within the subject vehicles.”
For Model Year 2015-2016 trucks, the investigation focuses on the behavior of Ford’s 6-speed 6R80 automatic transmission. The later 2017s could be equipped with the 6R80 or the early version of the now-widespread 10-speed 10R80 transmission.
ODI says it identified 329 Vehicle Owners Questionnaires (VOQs) related to the investigation. Of those, 60% (197 people) were interviewed to confirm the details of their complaints. Those customers reported that their trucks regularly and repeatedly downshifted to a low gear — most commonly 1st or 2nd gear — with no prior warning. 43% of the customers interviewed said they personally experienced the rear wheels locking up at least once.
In its preliminary investigation, Ford noted a defect in which the transmissions’ molded leadframe (which serves as the the internal wiring harness housing critical sensors) experienced supplier production issues. Those defects degraded electrical connections over time, exacerbated by thermal cycling and vibration. Over time, the problem could lead to signal loss from the Output Shaft Speed (OSS) sensor, as well as the Transmission Range Sensor (TRS).
“Signal loss from the TRS can result in an unintended shift to neutral, unintended upshift, or unintended downshift which are regulated by a gear “shift map” based on the vehicle’s speed at the time of signal loss,” the early report reads. For example, between 35-64 mph, the maximum allowable downshift would be from 6th to 2nd gear, in which Ford identifies the “worst-case scenerio” would be temporary rear wheel lockup.
The purpose of this engineering analysis is to look at the transmissions in questions and their individual components. From there, the NHTSA will assess more technical information surrounding the connector degradation in the OSS and TRS sensors Ford mentions. This is not yet a full-scale recall campaign for the 1.3 million trucks involved in the probe. However, this investigation follows earlier transmission-related recalls for these late 12th-generation and early 13th-generation F-150 trucks, so it’s possible a recall could happen, depending on the agency’s findings.
For more information, you can read the full details of the engineering analysis on the NHTSA’s website (number EA26001).
