47
POWER TRAIN
The hydrostatic drive system is now electronically controlled by the Machine ECM through
four pump control solenoids. The joysticks send a signal to the ECM when moved by the
operator. The ECM sends corresponding signals to the pump control solenoid valves, which
control pump output flow to the travel motors.
Each motor includes a speed sensor for the feedback signal to Machine ECM. The ECM also
receives input from the engine speed sensor and the throttle lever position sensor to control the
underspeed function. The speed sensing valve has been eliminated.
The travel pilot solenoid and park brake solenoid have been eliminated and replaced by the
travel pilot ON/OFF solenoid valve located on the hydrostatic pump. The park brake switch
sends a signal to the ECM to control the park brake function.
The creeper switch sends a signal to the Machine ECM, which allows the operator to select a
maximum machine travel speed at full joystick movement.
A two-speed valve is also located on the pump if the machine is equipped with the optional
two-speed motors.
SERV1833-01 - 49 - Text Reference
07/08