Patent ID: 7377354

Claim:
A hydrostatic propulsion system for a vehicle, comprising: a fluid displacement pump; four fluid displacement motors, with left front and right front motors and left rear and right rear motors; a hydrostatic circuit fluidly connected to the pump and motors in a closed loop; and a traction control valve system having first and second one-way relief valve lines connected to the hydrostatic circuit, wherein the first one-way relief valve line flows in a first direction and the second one-way relief valve line flows in a second direction opposite to the first direction; wherein the pump is connected in the hydraulic circuit in a closed parallel/series arrangement with the fluid displacement motors, where the left front and right front motors are connected in parallel with an outlet of the pump, the left rear and right rear motors are connected in parallel with an inlet of the pump, the left front motor is connected in series with the right rear motor, and the right front motor is connected in series with the left rear motor.