Differential Unit problems of the 2016 Ford F-150

The contact owns a 2016 Ford F-150. The contact stated while driving at undisclosed speeds, there was a grinding and loud humming sound coming from the vehicle. The vehicle was taken to the dealer where it was diagnosed with rear-end failure. The rear-end including the rear differential was replaced; however, the failure recurred. The vehicle was taken to the same dealer where it was diagnosed with the same failure. The vehicle was not repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 66,000.

While driving straight ahead at a steady 35 mph on a 2% downgrade, small city, double lane, one-way, debris free street, the automatic transmission shifted abruptly from 4th gear to 1st gear. I did not make any gear shift lever changes nor did I change any options such as pushing the sport mode, tow mode,locking differential, hill descent or traction control buttons. I was seated confortably, both hands on the steering wheel, seat belt fully engaged with no in-vehicle distractions such as a phone or radio tuning. The engine immediately raced to 6400 rpm causing the rear wheels to start a skid even though the road surface was dry and free of any debris. After approximately 4 seconds I realized that the transmission had forceably, on its own, shifted into 1st gear, so I put the transmission into neutral. The dash mounted gear indicator showed 4th gear during this altercation which made it harder to know what was going on until I shifted to neutral. Although it took another 5 seconds for the transmission to respond fully to this input, it finally went into neutral. Shortly thereafter the rear wheels went into coast mode. I was able to narrowly avoid colliding with the vehicles in the left lane because of my quick corrective action of putting the transmission gear selector into neutral. I've not had this dangerous self-shifting transmission to 1st gear at highway speed occur but the one time on September 19, 2019, but it does still concern me. My truck had approximately odometer 32,000 miles at the time of this occurance. I bought the truck new with 16 miles and have not modified or poured any additives into the transmission. My truck has not been abused or towed. I sincerely hope this doesn't happen to any aother 2016 f150 truck owners, but perhaps, unfortunately it may have. I also hope this helps in maybe finding a fix should there need to be one.

At 15000 miles the front differential bearings began to fail and contaminated the entire front differential. The differential had to be completely replaced. This could have failed on the road leaving me stranded. This was while driving on normal city streets and the highway.