Patent ID: 7344469

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 first and second gearsets, said first gearset having a first sun gear, a first ring gear, a first planet carrier and a set of first planet gears rotatably supported by said first planet carrier and meshed with said first sun gear and said first ring gear, said second gearset having a second sun gear, a second ring gear coupled to said first planet carrier, a second planet carrier coupled to said first axleshaft and a set of second planet gears rotatably supported by said second planet carrier and meshed with said second sun gear and said second ring gear, said first brake is operable for selectively braking rotation of said first sun gear, said second brake is operable for selectively braking rotation of said second sun gear, and said friction clutch is operable for selectively coupling said first planet 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.