Patent ID: 7770685

Claim:
A vehicle comprising: a frame having a front end and a rear end; a first traction member operably coupled to the front end of the frame; a second traction member operably coupled to the rear end of the frame; a first hydraulic motor operably coupled to the first traction member for driving the first traction member in motion; a second hydraulic motor operably coupled to the second traction member for driving the second traction member in motion; a hydraulic pump fluidly coupled to the first hydraulic motor and the second hydraulic motor; a first positive displacement flow divider positioned intermediate the hydraulic pump and the first and second hydraulic motors, the first positive displacement flow divider being configured to divide the flow of hydraulic fluid from the hydraulic pump to the first and second hydraulic motors and to provide a differential lock so that during a first mode of operation the speed of the first hydraulic motor is substantially fixed relative to the speed of the second hydraulic motor; and a crossover orifice in fluid communication with a fluid path from the first positive displacement flow divider to the first hydraulic motor and a fluid path from the first positive displacement flow divider to the second hydraulic motor, the crossover orifice configured to provide a bypass so that during a second mode of operation the speed of the first hydraulic motor may vary relative to the speed of the second hydraulic motor.