Abstract: The field of the invention is one in which an electric motor drives a helically grooved shaft to displace a hydraulic fluid pumping piston to feed the hydraulic fluid under pressure through a flow directing and control system to energize the motion of a piston on a helically grooved second shaft to drive the second shaft which is able to supply the motion power to drive a vehicle, or to provide power to drive a shaft for other useful purposes, and to apply the mechanical advantage to be developed between pistons having a small and a large area relationship in a closed hydraulic fluid circulating loop where electric drive for one piston results in power output from the other piston.