The contact owns a 2015 Ford F-150. The contact stated that while her husband was driving 35 MPH, the transmission downshifted to a lower gear unexpectedly. There were no warning lights illuminated. The contact stated that initially, the vehicle would sporadically downshift to a lower gear. After a year, the vehicle started to sporadically downshift more frequently. The vehicle was taken to an independent mechanic, where it was diagnosed that the transmission needed to be replaced. The vehicle was repaired with the installation of a new transmission. The dealer was not made aware of the failure. The manufacturer was not made aware of the failure. The failure mileage was approximately 90,000.