Abstract: In a four-wheel drive motor vehicle with a primary drive axle and a secondary drive axle, at least one secondary drive axle coupling of the limited slip type is provided in the powertrain between the engine of the vehicle and the secondary drive axle. A primary drive axle coupling of the limited slip type is provided for the primary drive axle.

Abstract: An all-wheel drive system for a vehicle having an engine and a drive shaft is arranged between the drive shaft and front and rear propellable shafts. These shafts are interconnected by first and second clutches respectively, and the propellable shafts are coupled to front and rear wheels, for transferring torque from the drive shaft to the front and/or rear wheels. The all-wheel drive system further includes at least first and second actuators that are coupled to at least first and second clutches, where at least the first clutch is engaged by a spring and at least the first actuator is coupled for disengaging the first clutch when the first actuator is operated. The second actuator is coupled for engaging the second clutch when the second actuator is operated.

Abstract: A device for transmitting torque between two rotatable, coaxial shaft members (1, 2) contains a clutch (35) between the two shaft members and engageable—to counteract rotational speed differential between the shaft members—by a hydraulic piston (18) under the control of an electrically controlled throttle or pressure valve (26), and a clutch pump (36) for supplying hydraulic pressure to the hydraulic piston, the clutch pump being driven by either one or both of the shaft members. The hydraulic piston (18), the valve (26), and the clutch pump (36) are connected in a hydraulic system also containing a feeder pump (31) for maintaining a certain base pressure in the system. The hydraulic system conditionally allows flow from the feeder pump (31) past the valve (26) to the hydraulic piston (18) irrespective of the flow from the clutch pump (36).

Abstract: A device for transmitting torque between two rotatable, coaxial shaft members contains a clutch between the two shaft members and engageable to counteract rotational speed differential between the shaft members by a hydraulic piston under the control of an electrically controlled throttle or pressure valve, and a clutch pump for supplying hydraulic pressure to the hydraulic piston, the clutch pump being driven by either one or both of the shaft members. The hydraulic piston, the valve, and the clutch pump are connected in a hydraulic system also containing a feeder pump for maintaining a certain base pressure in the system. The hydraulic system conditionally allows flow from the feeder pump past the valve to the hydraulic piston irrespective of the flow from the clutch pump.

Abstract: A device for transmitting torque between two rotatable, coaxial shaft members (2, 4) has a number of alternate clutch discs (5, 6), connected to the two shaft members and engageable to counteract differential rotational speed between the shaft members. The rotational movement may be braked by braking means (26-28), whose rotational velocity is proportional to the rotational speed differential. Means for transmitting the rotational speed differential to the braking means comprises a roller arrangement (20-25).

Abstract: Torque is transmitted between two rotatable, coaxial shaft members in a stationary housing which includes a number of alternate clutch discs connected to the shaft members and engageable to counteract differential rotational speed therebetween, and a hydraulic arrangement driven by the speed differential. The arrangement includes a number of pistons which are axially movable in the housing and are intended to create a hydraulic pressure in the arrangement and thereby to engage the clutch discs, piston actuating devices engaging a shaft member via cams, so as to impart to the pistons a reciprocating movement, and a closed hydraulic system connecting cylinders at all pistons with a hydraulic line containing check-valves. Oil is supplied to the system with a pump and may be removed from the system via an overflow valve.