an aperture 40 is positioned a line 39 leads from the fourth clutch cooling system port 34 to the clutch cooling system in addition a port 42 is provided on the valve chamber 1 and is connected via a line 43 to the cooling system return line furthermore a port 46 is provided on the valve chamber 1 and is connected via a line 47 to the suctioning tract of the pump via a port 49 the space that houses the helical compression spring 24 is connected to a tank via the port 49 it is ensured that the space that houses the compression spring 24 remains pressureless finally the valve chamber 1 is equipped with a port 50 which is connected via a line 51 to a source of pilot pressure the first clutch cooling system port 31 is connected to the first end face 17 of the first actuating piston 11 when the first actuating piston 11 is in the position shown in fig1 the second clutch cooling system port 32 is connected to the cooling system return line port 42 via the center section 16 of the first actuating piston 11 however the second clutch cooling system port 32 can also be closed off by the circular cylindrical section 14 of the first actuating piston 11 when the valve is in the operating positions shown in fig1 and 2 the section 21 of the second actuating piston 12 in the valve chamber 1 is arranged between the third 33 and the fourth 34 clutch cooling system ports hence there is no connection between the third.