Abstract: A selective all wheel drive powertrain has an engine and transaxle adapted to normally drive the front wheels of a vehicle. A transfer gear set, drive shaft, clutch and differential are connectable between the output of transaxle and the rear wheels of the vehicle to selectively provide an all wheel drive system. A pump, which supplies the fluid pressure to engage the clutch, has a pair of relatively rotatable members that are connected to rotate in unison with opposite sides of the clutch such that when the valve is operated, the clutch will be engaged. A selectively operable valve is disposed between a reservoir and the pump and controlled in actuation by the vehicle traction control system (TCS) to connect the pump to the reservoir when a loss of traction is sensed by the TCS. The clutch is effectively controlled by the selectively operable valve that supplies the fluid to the pump.

Abstract: An all wheel drive mechanism has a powertrain including an engine, transmission, front drive differential, a rear drive transfer gearing and a selectively operable rear drive mechanism. The rear drive mechanism has a housing, driven by the transfer gearing through a drive shaft. A pair of selectively engageable clutches, which are operable to connect the rear wheels to the housing, are disposed in the housing. A pair of pumps are assembled in the housing to provide operating fluid for the clutches. Each pump has one member secured for rotation with the housing and another member secured for rotation with respective rear wheel drive axles. An inlet of the pumps is controlled by a solenoid operated valve which is energized in response to an anti-lock brake system and traction control system of the vehicle. When energized, the valve connects the pumps to a reservoir such that fluid in the reservoir can be pumped to the clutches to enforce engagement thereof resulting in a drive path to the rear wheels.

Abstract: A vehicle body structure includes a perimeter frame including laterally spaced right and left side rails of tubular construction and front and rear bumper rails of tubular construction extending between the side rails. A structural tunnel extends longitudinally of the vehicle midway between the side rails and has front and rear ends. The structural tunnel includes an inverted U-shaped channel having vertically depending the first and second legs, and a close-out plate which extends horizontally between the legs. First and second front shear walls extend forwardly and diagonally from the first and second legs at the front of the tunnel to the respective right and left side rails of the perimeter frame. Similarly, first and second rear shear walls extend generally rearward and diagonally from the first and second legs at the rear end of the tunnel to the respective left and right side rails of the perimeter frame.