A control system controls a three point implement hitch assembly of a tractor. The three point implement hitch assembly includes an upper link and two lower links. The upper link includes an adjustable length double acting hydraulic unit. The position of each lower link is controlled by an adjustable length double acting hydraulic unit. A hydraulic circuit controls communication between the hydraulic units, a hydraulic supply and a hydraulic tank. The circuit permits each hydraulic unit to be controlled independently of one another.