DOOR AS 5N6189 - Caterpillar

Charge Pump System
The hydrostatic drive system utilizes charge pumps (17) in order to replenish oil that is lost due to normal leakage. The charge pumps also control the supply pressure to drive pumps (16) and (30). Each of the drive pumps has a charge pump. The system also contains the following components:
charge relief valve (11)
makeup and line relief valves (19) and (31)
purge shuttle valves (14) and (29)
purge relief valves (3) and (28) In normal operation, charge pumps (17) provide flow to the drive loop. This flow replenishes lost oil due to leakage in the drive loop. Excess charge pump flow is relieved over charge relief valve (11). Charge pressure relief valve (11) limits maximum pressure of the charge oil.There are four makeup and line relief valves (19) and (31) to the drive pumps in the system. Each drive pump (16) and (30) has two makeup and line relief valves.Makeup and line relief valves (19) and (31) limit the maximum pressure in the high pressure side of the loop.Purge shuttle valves (14) and (29) are located in drive motors (4) and (37). The FORWARD and REVERSE pressure side of the loop push on the ends of the purge valve spool in the purge shuttle valves of the drive motors.The high pressure side of the drive loop shifts the spool, which opens the low pressure side of the loop to purge relief valves (3) and (28) of drive motors (4) and (37) .Oil that flows across purge relief valves (3) and (28) combine with the excess charge pump flow that is relieved over charge relief valve (11). This combined flow passes through cooler (41). Then, the flow is used to flush drive pumps (16) and (30) and drive motors (4) and (37). This flushing oil performs two functions: cooling the pumps and motors and flushing the contaminants that could possibly cause damage.Drive Pump and Motor
The operator must be able to control the speed of the machine and the direction of the machine. To control the machine, movement of the speed/direction control lever to a particular position in the operator compartment sends an electronic signal to the Electronic Control Module (ECM).
Illustration 2 g00710367
Electronic Control Module (ECM)Note: The Electronic Control Module (ECM) is located toward the front of the right access door. Refer to the Systems Operation/Testing and Adjusting, SENR8314, "953C, 963C & 973C Track-Type Loaders Hydrostatic Transmission Electronic Control System", "Electronic Control Module (Hydrostatic Transmission)" for information. You must refer to revision 03 or you must refer to a newer revision. Older versions do not have the appropriate information for the 973C. The signal from the speed/direction control lever in the operator compartment is then analyzed in the ECM and a signal is sent to the selected solenoid valve on ECM manifold (F) .ECM manifold (F) sends pilot pressure to drive pumps (16) and (30) and to drive motors (4) and (37) .The pilot pressure oil to drive pumps (16) and (30) and to drive motors (4) and (37) flows to