Abstract: A hydraulic system for use in the propulsion of motor vehicles includes at least two volume multipliers each having a high pressure port, a low pressure port, and a piston in a chamber separating the high and low pressure ports. A prime mover and associated main hydraulic pump is arranged to alternately supply high pressure fluid to the high pressure ports of the multipliers, so as to produce a reciprocating motion in the pistons and create a continuous flow of high pressure fluid from a reservoir through the pump, into the high pressure port of one volume multiplier, out of the high pressure port of the other multiplier, and back to the reservoir. The reciprocating pistons are used to create a second, separate continuous flow of low pressure hydraulic fluid which circulates from the low pressure port of one volume multiplier through one or more hydraulic driving motors adapted to propel the vehicle, and back to the low pressure port of the remaining multiplier.