Abstract: An all wheel drive system for a motor vehicle is normally set up to operate in a two wheel drive mode except in vehicle operating situations where increased traction is desired. A drive shaft of a drive line is connected to front and rear axles through respective speed adjusters. A front speed adjuster provides for transmitting a rotational speed to the front drive axle that is slower than a rotational speed transmitted by the rear speed adjuster to the rear drive axle. At least one overrunning clutch is interposed in the drive line to a pair of front drive wheels for permitting the front drive wheels to be rotated out of engagement with the drive line by motion of the vehicle.