The official notice
Defect
On certain trucks, the rear axle tube could deform at the spring seat attachment points. As a result, the driveshaft could detach from the rear axle and cause a loss of power to the wheels. If this happens, the truck could also move when the transmission is in Park, and the parking brake is not used. Note: This recall only affects single rear wheel trucks with a 6.7 L diesel engine.
Safety Risk
A loss of power to the wheels 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 inspect the rear axle. If the rear axle housing is deformed, the housing will be replaced. If the housing is not deformed, the dealer will repair the spring seat attachments.