Patent ID: 7588508

Claim:
A vehicle comprising: a primary powertrain providing a primary source of propulsive power; a first axle receiving propulsive power from the primary powertrain and transmitting power to a first set of vehicle wheels; and a drive train module for selectively providing propulsive power to a second set of vehicle wheels, the drive train module including a second axle assembly and an auxiliary drive, the second axle assembly having a housing, a differential unit, an input shaft, a pair of drive shafts and a pair of wheel hubs, the differential unit disposed in the housing for rotation about a differential axis, the input shaft being disposed in the housing for rotation about an input shaft axis that is transverse to the differential axis, the differential unit including a case and a bevel ring gear that is coupled to the case, the input shaft having a bevel pinion that is meshingly engaged to the bevel ring gear, each drive shaft coupling the differential unit to an associated one of the wheel hubs, the auxiliary drive having an electric motor and an overrunning clutch, the electric motor having an output shaft that is coaxial with the input shaft, the overrunning clutch including an input portion, which is coupled to the output shaft, and an output portion, which is coupled to the input shaft, the output portion being de-coupled from the input portion when a rotational speed of the input portion is not greater than a rotational speed of the output portion.