Transmission failure which resulted in significant loss of power when shifting gears while pulling onto a major road. This caused the vehicle to stall which could have resulted in multi car accident as well as harm to those in vehicle(s). Additionally, there have been multiple hard shifts when accelerating as well as loss or skipping of gears when traveling on the interstate. This has also happened from a stop when turning at intersections, with the transmission falling out of gear completely while driving, causing an unexpected loss of power in traffic. There were no check engine or warning lights prior to these incidents happening. The vehicle has been inspected by a Ford dealership who confirmed a new transmission was necessary and said this model is a design flaw and there are known issues with this particular transmission. The check engine light will randomly come on then go away. Fortunately it had come on the way to the dealer for inspection so they pulled the truck right back and ran diagnostics.