Various embodiments may include a clutch assembly comprising: a first coupling and a second coupling; and a vibration damper with a spring. The first coupling includes a crankshaft connection and a coupling-in element which can be connected to one another in a controlled manner. The second coupling has an output connection and an intermediate element which can be connected to one another in a controlled manner. The spring connects the intermediate element and the coupling-in element to one another.

Various embodiments may include a clutch assembly comprising: a first coupling and a second coupling; and a vibration damper with a spring. The first coupling includes a crankshaft connection and a coupling-in element which can be connected to one another in a controlled manner. The second coupling has an output connection and an intermediate element which can be connected to one another in a controlled manner. The spring connects the intermediate element and the coupling-in element to one another.

A clutch hydraulic pressure control circuit includes: a shift valve for switching the destination to feed hydraulic pressure to a first hydraulic clutch or a second hydraulic clutch; and first and second shift solenoid valves operating synchronously to actuate the shift valve. The two shift solenoid valves include a holding valve for keeping hydraulic pressure fed to the shift valve even when hydraulic pressure supply through one of the first and second shift solenoid valves happens to be shut off while hydraulic pressure is fed through the first and second shift solenoid valves to paths between the shift valve and the shift solenoid valves, or when hydraulic pressure supply through one of the first and second shift solenoid valves happens to occur while no hydraulic pressure is fed through the shift solenoid valves.

A power unit includes a transmission adapted to transmit rotational power from a crankshaft to a drive axle, with speed change. The transmission has an input shaft rotatably supported on a crankcase. A hydraulic clutch, configured to be selectively engaged and disengaged, is disposed coaxially with the input shaft. A clutch cover covering the hydraulic clutch is connected to the crankcase. A clutch actuator, which controls switching between engagement and disengagement of the hydraulic clutch, and an actuator cover, which covers the clutch actuator in a liquid-tight manner, are mounted to an outer surface of the clutch cover. An oil temperature sensor is mounted to the actuator cover, and is provided for detecting a temperature of oil in an oil chamber, formed between the clutch cover and the actuator cover.

A clutch hydraulic pressure control circuit includes: a shift valve for switching the destination to feed hydraulic pressure to a first hydraulic clutch or a second hydraulic clutch; and first and second shift solenoid valves operating synchronously to actuate the shift valve. The two shift solenoid valves include a holding valve for keeping hydraulic pressure fed to the shift valve even when hydraulic pressure supply through one of the first and second shift solenoid valves happens to be shut off while hydraulic pressure is fed through the first and second shift solenoid valves to paths between the shift valve and the shift solenoid valves, or when hydraulic pressure supply through one of the first and second shift solenoid valves happens to occur while no hydraulic pressure is fed through the shift solenoid valves.

A dual clutch for coupling an engine drive shaft with a transmission shaft and/or an auxiliary power take-off. A first friction clutch presses a first clutch plate that is couplable with the transmission shaft between a first contact plate, displaceable in an axial direction to engage the first friction clutch and a first counter plate. A second friction clutch presses a second clutch plate that is couplable with the auxiliary power take-off between a second contact plate, displaceable in the axial direction to engage the second friction clutch and a second counter plate. First and second actuating elements move the first and second contact plates; respectively. The second contact plate is connected to a thrust ring connected to the second actuating element to transfer displacing movement. The second actuating element has a spring element, situated between the second actuating element and the thrust ring, for pre-stressing so that a reduction of contact force is avoided in case of wear and tolerance dependency of the contact force and/or actuating force is decreased.