On certain trucks, the left-rear axle shaft may not have been manufactured properly. As a result, the axle shaft could break and cause a loss of power to the wheels. Additionally, if the truck is parked and the parking brake is not applied, the truck could roll away.
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.
Ford will notify owners by mail and advise you to take your truck to a dealership to inspect the left-rear axle shaft, and replace it as necessary.