TUBE ASSEM. 9M6012 - Caterpillar

When the machine is equipped with two-speed capability, the machine can be switched to rabbit mode. A control switch is mounted on the travel control lever (36) which activates the two-speed function.The two-speed control switch (36) is a momentary switch. When the multifunction switch (37) is in the TWO-SPEED position, press the button once in order to activate the rabbit mode. Press the switch again in order to deactivate the rabbit mode and return to the normal mode. When the machine is in the normal mode, the hydrostatic system functions in the same manner as machines equipped with the standard piston motors. Refer to the Operation and Maintenance Manual, "Operator Controls (Joystick Controls)" for additional information.When the operator presses the two-speed control switch (36) in order to activate the rabbit mode, the switch sends an electrical signal to the solenoid valve group (two-speed control) (26). Since the solenoid in the solenoid valve group (two-speed control) is now energized, the spool that is part of the solenoid valve group (two-speed control) shifts to the left. When the spool is shifted to the left, the spool will allow charge oil to flow to the port that is for the two-speed control. The oil then flows to the speed selector valve (32) that is a part of the piston motor group (hydrostatic left side) (25) and the speed selector valve (32) that is a part of the piston motor group (hydrostatic right side) (28).When the charge oil pressure is greater than the force of the spring that is positioning the speed selector valves, the charge oil pressure forces the selector valves to shift downward. When the speed selector valves are shifted downward, the speed selector valves will block the flow of high-pressure oil from port (21) or port (23) to half of the pistons in the motors. The cylinders that do not receive oil (12) will then freewheel as the motor shaft spins. Because only half of the pistons receive oil flow, the oil can fill the cylinders faster. The faster filling cylinders cause the motor shaft to rotate faster. The output torque of the motor will decrease with the increase in speed.When the machine is first started, the machine is automatically reset to the normal mode.Piston Motor Group (Two-Speed) for Compact Track Loader Machines
Illustration 9 g06253030
(1) Case drain (port)
(3) Brake release (port)
(4) Port for the "A" or "B" high-pressure loop
(5) Speed sensor connection
(7) Port for the two-speed control
(8) Port for the "A" or "B" high-pressure loop
Illustration 10 g06253032
(2) Fill/Drain port
Illustration 11 g02841717
(9) Swashplate
(10) Pistons
(11) Passage from speed selector valve (6) to piston (10)
Illustration 12 g02841736
Hydraulic schematic for the two speed
(3) Brake release
(4) High-pressure line for the "A" or "B" high-pressure loop
(6) Speed selector valve
(8) High-pressure line for the "A" or "B" high-pressure loop
(10) Piston that controls the swashplate angle
(11) Passage from speed selector valve (6) to piston (10)
( 12) Piston motor (hydrostatic left side)
(13) Solenoid valve (two-speed control)
(14) Line to the return manifold
(15) Piston motor (hydrostatic right side)
(16) Charge oil supplyIf the piston motor