A hybrid drive system for a four-wheel drive system arranged to supply
motive power to a first output shaft of a transfer case from an internal
combustion engine and to a second output shaft from an electric
motor/generator. The transfer case includes a reduction gearset driven by
the electric motor/generator, a power take-off unit driven by the
reduction gearset, and a disconnect clutch operable for selectively
coupling the reduction gearset to the second output shaft. This hybrid
drive arrangement permits installation of a modified transfer case in
place of a conventional transfer case for use in a traditional four-wheel
drive driveline arrangement.