Abstract: A power transmission is provided characterized by smoothly and continuously variable gear ratios between the input and output shaft by incorporating a no-load restraint means for the ring gear of a ring, planetary and sun gear transmission system, the restraint comprising a wobble plate pump operative in a closed liquid circuit and driven by said ring gear to impose a restraint on same which varies according to an external control of the angle of the wobble plate and also including a second wobble plate pump in the same closed line or loop as the first pump and which is driven by the output shaft and whose liquid displacement capabilities per cycle is determined as a function of the wobble plate angle which may be controlled either manually or by the pressure at the liquid output line from the first pump.