Abstract: An automotive drive unit provided with a rotatably driveable input shaft and at least one output shaft driven by the input shaft, a hydraulic clutch responsive to differences in rotation between the input and output shafts and provided with a hydrostatic displacement pump which at the occurrence of such a difference generates pressure for reducing the difference. The pressure fluid is drawn by the pump from a stationary reservoir into a suction chamber by way of a suction tube. In order to minimize the structural complexity of the drive unit and to provide a precise and quickly responsive control, the suction chamber is limited by a wall integral with the housing of the drive unit, and the suction tube is provided with a selectively controllable valve.