Patent ID: 7665564

Claim:
A power train for a vehicle, the vehicle having a frame, an engine mounted to the frame and having a rotatable engine output shaft, and front and rear axles each rotatably connected with the frame, each axle including two axle shafts and two wheels, each wheel being connected with a separate one of the axle shafts and rollable upon a base surface, the power train comprising: a transmission operably connected with the engine and having a transmission output shaft; a first propeller shaft having a first end, the first end being connected with the transmission output shaft, and a second end; a front differential connected with each one of the two front axle shafts and having a front differential gear member configured to rotatably drive the two front axle shafts, the front differential being operatively connected with the second end of the first propeller shaft such that the first propeller shaft drives the front differential gear member at a first speed reduction ratio; a second propeller shaft having a first end, the first end being connected with the transmission output shaft, and a second end; and a rear differential connected with each one of the two rear axle shafts and having a rear differential gear member configured to rotatably drive the two rear axle shafts, the rear differential being operatively connected with the second end of the second propeller shaft such that the second propeller shaft drives the rear differential gear member at a second speed reduction ratio, the first speed reduction ratio being greater than the second speed reduction ratio such that the base surface drives the two front axle shafts to rotate independently of the front differential gear member when at least one of the two rear wheels rolls upon the base surface, the rear differential being configured to releasably connect each one of the two rear axle shafts with the other one of the two rear axle shafts when each of the two rear wheels rolls at about the same speed as the other one of the two rear wheels such that the two rear axle shafts rotate generally as a single unit and to alternatively disconnect at least one of the two rear axle shafts from the other one of the two rear axle shafts when one of the two rear wheels rolls at a greater speed than the other one of the two rear wheels during a turning movement of the vehicle.