A vehicle having: a front pair of hydrostatically driven ground wheels (14, 16), in which steering is accomplished by applying differential hydraulic flow to respective hydraulic drive motors (26, 28) coupled to the front pair of driven ground wheels (14, 16), a pair of hydraulic pumps (46, 48) respectively coupled for supplying hydraulic fluid to the drive motors (26, 28) and including first and second displacement control levers (52, 54), a double-acting front steering cylinder having a piston rod coupled to a linkage including a selectively translatable and pivotal steering control plate coupled to the first and second displacement control levers (52, 54) for controlling the displacements of the pair of hydraulic pumps (46, 48), a hydro-lever selectively movable from a neutral, Park, position for initiating forward and reverse driving speeds of the vehicle, a manually operable primary front wheel steering control valve coupled for receiving steering inputs from a shaft operated by a steering wheel and having right and left steering fluid ports respectively coupled to right and left steering ports of the double-acting steering cylinder for actuating the steering cylinder piston rod for effecting pivotal movement of the control plate, with the primary steering valve having normal predetermined internal leakage of pressure fluid when actuated for supplying such pressure fluid to one or the other of the right and left steering fluid ports, a steering control arrangement comprising: an electronic control unit; a front steering input sensor coupled for sensing a steering input transmitted to the primary steering valve from the steering wheel and for generating a front steering input signal corresponding to the sensed steering input, with this steering input signal being coupled to the ECU; a vehicle speed sensor coupled for sensing forward ground speed of the vehicle and for generating a corresponding vehicle ground speed signal, with this ground speed signal being coupled to the ECU; an electro-hydraulic, automatic front wheel steering control valve coupled for selectively providing steering control fluid to first and second ports of the steering control cylinder and including a normally deactivated, electrically responsive enable valve arrangement (138, 148) electrically coupled to said ECU, and normally deactivated electrically responsive, right and left proportional front steering control valve arrangements (158, 178, 162, 192) electrically coupled to said ECU; and said ECU being operable for processing the steering input signal, the vehicle ground speed signal and the information relating to said normal amount of leakage, and for sending an enable signal to the enable valve arrangement (138, 148) and for selectively sending one of a proportional right steering signal or a proportional left steering signal to that one of the right and left proportional steering control valve arrangements (158, 178, 162, 192) corresponding to the direction of steering indicated by the steering input signal, thereby causing said one of the right and left proportional steering control valve arrangements (158, 178, 162, 192) to supply an amount of actuating fluid to the steering cylinder which is approximately equal to the normal, predetermined internal leakage of the primary steering valve. an electronic control unit; a front steering input sensor coupled for sensing a steering input transmitted to the primary steering valve from the steering wheel and for generating a front steering input signal corresponding to the sensed steering input, with this steering input signal being coupled to the ECU; a vehicle speed sensor coupled for sensing forward ground speed of the vehicle and for generating a corresponding vehicle ground speed signal, with this ground speed signal being coupled to the ECU; an electro-hydraulic, automatic front wheel steering control valve coupled for selectively providing steering control fluid to first and second ports of the steering control cylinder and including a normally deactivated, electrically responsive enable valve arrangement (138, 148) electrically coupled to said ECU, and normally deactivated electrically responsive, right and left proportional front steering control valve arrangements (158, 178, 162, 192) electrically coupled to said ECU; and said ECU being operable for processing the steering input signal, the vehicle ground speed signal and the information relating to said normal amount of leakage, and for sending an enable signal to the enable valve arrangement (138, 148) and for selectively sending one of a proportional right steering signal or a proportional left steering signal to that one of the right and left proportional steering control valve arrangements (158, 178, 162, 192) corresponding to the direction of steering indicated by the steering input signal, thereby causing said one of the right and left proportional steering control valve arrangements (158, 178, 162, 192) to supply an amount of actuating fluid to the steering cylinder which is approximately equal to the normal, predetermined internal leakage of the primary steering valve.