The official notice
Defect
On certain trucks, the insulation under the truck may loosen and damage the driveshaft. If this happens, the driveshaft could break and cause a loss of power to the wheels. A broken driveshaft could also contact the ground and cause a loss of control. Additionally, the truck could move when the transmission is in Park and the parking brake is not used. Note: This recall only affects certain SuperCrew 4x4 models with a 5.5' box that have specific options and an aluminum driveshaft.
Safety Risk
A loss of power to the wheels or a loss of control could increase the risk of a crash. A parked vehicle that rolls away could also create the risk of an injury or a crash.
Remedy
Ford will notify owners by mail and instruct you to take your truck to a dealer to add new attachments for the underbody insulators. The dealer will also inspect the driveshaft for damage and repair it, as necessary.