THE PRESENT DISCLOSURE PERTAINS TO A TRANSMISSION AND SPEED VARIATION DEVICE FOR AN AUTOMOTIVE VEHICLE, SUCH AS A HARVESTER COMBINE OR TRACTOR FOR DRIVING THE VEHICLE BOTH IN FORWARD AND REVERSE DIRECTIONS AT VARIOUS SPEEDS IN BOTH DIRECTIONS. THE DEVICE IS ACAPABLE OF ENGAGING AT WILL, INDEPENDENTLY OF ONE ANOTHER, AT LEAST TWO DRIVEN SHAFTS WITH A DRIVING SHAFT AND INCLUDES A SPEED CHANGING MEANS COUPLED TO AT LEAST ONE OF THE DRIVEN SHAFTS AND MEANS FOR AXIAL CLAMPING OF CONVENTIONAL CLUTCH PLATES.