Patent ID: 7503416

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 mode clutches and a brake, 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 and a first planet carrier coupled to said first axleshaft and rotatably supporting first planet gears that are 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 and a second planet carrier coupled to said first ring gear and rotatably supporting second planet gears that are meshed with said second sun gear and said second ring gear, said first mode clutch is operable for selectively coupling said first sun gear to one of said input component and said second output component of said differential assembly, said second mode clutch is operable for selectively coupling said first ring gear to the same one of said input component and said second output component of said differential assembly, and said brake is operable for selectively braking rotation of said second sun gear; and a control system for controlling actuation of said first and second mode clutches and said brake.