Patent ID: 7004876

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, first and second speed changing units, and first and second mode clutches, said differential 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 first speed changing unit having a first sun gear driven by said first output component, a first ring gear, and a set of first planet gears meshed with said first sun gear and said first ring gear, said second speed changing unit having a second sun gear driven by said second output component, a second ring gear, and a set of second planet gears meshed with said second sun gear and said second ring gear, said first mode clutch is operable for braking rotation of said first ring gear, and said second mode clutch is operable for braking rotation of said second ring gear; and a control system for controlling actuation of said first and second mode clutches.