Abstract: A coupling for an AWD vehicle comprises a disc package with alternate discs (6,7; 56, 57; 76, 77), which are connected for rotation with, but are axially movable in relation to an ingoing (1; 52, 71) and an outgoing axle (2; 51; 72), respectively, of the coupling, and a hydraulic piston (9; 59; 79) for pressing the disc package together under the action of hydraulic pressure, hereby establishing a connect mode, in which the ingoing axle is connected to the outgoing axle. A coupling slack adjuster (13-15; 64, 65; 83-85) is provided for mechanically establishing a rest position for the hydraulic piston (9; 59; 79) in a disconnect mode, in which a predetermined slack in the disc package is established, irrespective of the wear of the discs.

Abstract: A method of controlling a drive train comprising an electric motor (12), a gearbox (1) and an internal combustion engine (13). The gearbox (1) is placed between the electric motor (12) and the internal combustion engine (13) in the drive train. The speed of the electric motor (12) is synchronized to the speed of the internal combustion engine (13) in order to shift the gearbox. The gearbox (1) is shifted between different operation modes by means of controlling the position of a dog clutch (6).

Abstract: In a hydraulic system with a dog clutch (23-25), a hydraulically operated dog clutch actuator is arranged to alternatively bring the dog clutch into a connect mode or a disconnect mode. The clutch actuator has a piston (27) reciprocally movable under hydraulic pressure between two end positions, corresponding to the two clutch modes. Pressurized hydraulic oil is supplied to the clutch actuator by a hydraulic power system comprising a pump (4) driven by an electric motor (3). Means are provided in the clutch actuator to decrease the hydraulic pressure acting on the piston (27) at the approaching by the piston of either of its end positions, so that a hydraulic signal is transmitted back to the hydraulic power system.