Compared with automotive power transmission systems, commercial vehicle drive systems are very large, heavy, complex and have far more demands and problems. Trucking companies are interested in any technologies that can potentially reduce the cost and weight of the tractors. of reduced tractor weight,  Because commercial vehicles have a gross weight limit, reduced tractor weight effectively increases the cargo capacity of semi-trailers in addition to the expected efficiency advantages.

Variable displacement hydrostatic pumps and motors are used to drive the wheels of many large commercial vehicles but thus far none have been successfully adapted to highway vehicles due to lower efficiency at higher speeds. Associated with this project proposal is a patent pending variable displacement hydrostatic pump/motor design that the inventor believes will have an extended efficient speed range than current hydrostatic motor designs and also a lower manufacturing cost.

Three variable displacement reversible hydrostatic motors could be mounted on a drive axle to implement a complete transmission system. Microprocessor control can add sophisticated functions such as skid control al contained in an axle that could be easily retrofit to existing fleets of trucks.