Patent ID: 7491146

Claim:
A motor vehicle, comprising: a powertrain operable for generating drive torque; a primary driveline for transmitting drive torque from said powertrain to first and second primary wheels; a secondary driveline for selectively transmitting drive torque from said powertrain to first and second secondary wheels, said secondary driveline including an input shaft driven by said powertrain, a first axleshaft driving said first secondary wheel, a second axleshaft driving said second secondary wheel and a drive mechanism coupling said input shaft to said first and second axleshafts, said drive mechanism including a differential assembly, a planetary gear assembly, first and second brakes and a friction clutch, said differential assembly having an input component driven by said input shaft, a first output component driving said first axleshaft and a second output component driving said second axleshaft, said planetary gear assembly having a first gear, a second gear, a first carrier, a third gear rotatably supported by said first carrier and meshed with said first gear and said second gear, a fourth gear, a fifth gear driven by said first carrier, a second carrier coupled to said first axleshaft, and a sixth gear rotatably supported by said second carrier and meshed with said fourth gear and said fifth gear, said first brake is operable for selectively braking rotation of said first gear, said second brake is operable for selectively braking rotation of said fourth gear, and said friction clutch is operable for selectively coupling said first carrier to one of said input component and said second output component of said differential assembly; and a control system for controlling actuation of said first and second brakes and said friction clutch.