<p>In a hydrostatic torque transmitting mechanism a switching hysteresis between a high torque (M) and a low torque (N) transmission characteristics is achieved by means of a centrifugally actuated check valve. When a predetermined first vehicle velocity (V1) is reached, a weight pivots to allow the check valve to open, thereby effecting a switching (O) from said high torque (M) to said low torque (N) transmission characteristic. When the vehicle velocity drops to a second value (V2) lower than the first (V1), said weight returns to its original position to close the check valve, thereby effecting a switching (Q) from said low torque (N) to said high torque (M) transmission characteristic. <IMAGE></p>
