Ford 1983½ Ranger/Bronco II 4×4 light trucks will be available with optional automatic locking hubs manufactured by Warn Industries. The design has been developed with Ford Light Truck Engineering to provide superior reliability, in addition to improved fuel economy and customer convenience which are inherent in the design.This paper traces the evolution from conception to production of the Warn Industries' proprietary sliding clutch ring (referred to as SCR) automatic locking hub. This automatic locking hub is similar in function to the well accepted, and proven, manual hub lock used as standard equipment on all Ford 4×4 light trucks. However, when the transfer case is placed in four-wheel drive, these hubs automatically engage the front wheels with the driving axle. Getting out of the vehicle to manually turn a dial on each of the hubs to either engage or disengage the front driving axle is not required. In two-wheel drive when the hubs disengage, all front drivetrain components are stationary, thereby providing improved fuel economy and eliminating unnecessary drag and wear on the front axle, drive shaft and transfer case components. In other competitive designs, however, some of the drivetrain components continue to rotate in two-wheel drive.Because the automatic locking hubs offer greater operating convenience, they reduce the amount of time the hubs are locked — a significant step toward improved fuel economy.