Abstract: A hydraulic parking brake controller for a motor vehicle for controlling the operation of a parking brake of the transmission output-shaft mounted type in response to the operating unit. The controller comprises a primary control and a secondary control. The primary control actuates and releases the parking brake at a first rate. The secondary control actuates the parking brake at a second rate slower than the first rate in an instance in which the parking brake is in the released state and the operation unit malfunctions. If a circuit break should occur in the operation unit while the parking brake is in the released state, the secondary control actuates the parking brake at the second rate. The parking brake is thus not actuated suddenly in the event of an abrupt wire disconnection, such that the braking action is dampened.

Abstract: A working oil is supplied to a first set of clutch through a first control valve when the first control valve is functioning. The working oil is supplied to a second set of clutch through a second control valve, a third control valve and a fourth control valve when the second control valve is functioning and third and fourth control valves are not functioning. The working oil is supplied to a third set of clutch through the second control valve, the fourth control valve and the third control valve when the second and third control valves are functioning and the fourth control valve is not functioning. The working oil is supplied to a fourth set of clutch through the second control valve and the fourth control valve when the second and fourth control valves are functioning.

Abstract: A differential limiting device is provided for use in a differential mechanism adapted to divide and transmit a torque from an input shaft to two output shafts. The device includes an oil pump driven by the difference in revolution speed between two shafts selected from the input shaft and output shafts, a wet clutch equipped with two types of disks and adapted to connect said selected two shafts to each other by the pressure of a working oil discharged from the oil pump, and an orifice-equipped lubricating passage for jetting out the working oil, which has been discharged from the oil pump, toward the disks of the clutch in order to avoid possible burnout of the disks.