Abstract: An improved hydraulic drive system is provided for a vehicle having a plurality of ground engaging wheels which are each individually driven by a hydraulic motor to provide all wheel drive. The ground engaging wheels include a first pair of such wheels at or adjacent a first end of the vehicle and at least one other such wheel at or adjacent a second end of the vehicle. The hydraulic drive system includes a hydraulic flow circuit that connects the hydraulic motors for the wheel(s) at the second end of the vehicle in series to each other, to the fluid source, and to the drive motors for the wheels at the first end of the frame, which latter drive motors are connected in parallel to each other. Such a vehicle will provide superior traction ability as at least one wheel on each end of the vehicle must slip to bring the vehicle to a halt.

Abstract: An improved hydraulic drive system is provided for a vehicle having a plurality of ground engaging wheels which are each individually driven by a hydraulic motor to provide all wheel drive. The ground engaging wheels include a first pair of such wheels at or adjacent a first end of the vehicle and at least one other such wheel at or adjacent a second end of the vehicle. The hydraulic drive system includes a hydraulic flow circuit that connects the hydraulic motors for the wheel(s) at the second end of the vehicle in series to each other, to the fluid source, and to the drive motors for the wheels at the first end of the frame, which latter drive motors are connected in parallel to each other. Such a vehicle will provide superior traction ability as at least one wheel on each end of the vehicle must slip to bring the vehicle to a halt.