Roland.O
Administrator
This is an extremely dangerous problem where the truck suddenly drops into 1st while traveling at high speed causing severe/catastrophic deceleration. This is caused by a faulty Output Shaft Speed Sensor(OSS) that sends incorrect speed data to the powertrain control module. The solution is to replace the transmission lead frame connector assembly which contains the speed sensors.
The F-50 is a highly advanced vehicle with a multitude of sensors and electronics. I advise owners to get a copy of the 2020 Ford F-150 Service and Repair manual-it will save you a lot of problems. It contains guideliness on how to maintain and repair the complex systems. I have provided the link to original OEM manual below.
Download it here: 2020 Ford F-150 Service and Repair Manual