Abstract: A scraper is provided with a hydrostatic rear wheel assist that is operated by foot pedals in the operators cab. A reversible variable displacement hydrostatic pump is operatively coupled to an engine mounted to the front frame section of the scraper. An engagement/disengagement valve is hydraulically positioned between the pump and the rear wheel hydraulic motors. The engagement/disengagement valve has two positions: a engagement position for directing pressurized hydraulic fluid to the motors and a disengagement position for preventing the flow of pressurized hydraulic fluid to the motors. In its disengagement position the wheel motors are free to free wheel as the motors are coupled to sump. A traction control valve is positioned between the engagement/disengagement valve and the wheel motors. The traction control valve has an uncontrolled flow divider position and a differential lock or controlled flow divider position. Both valves are operated by an electrical controller.