HYDROSTATIC PUMP AND MOTOR EFFICIENCY TEST
WARN I N G
DO NOT disconnect or remove any hydraulic system hoses, tubes, or fittings unless
engine is shut down and hydraulic system pressure has been relieved. Escaping hydraulic
fluid under pressure can penetrate skin.
At operating temperature, hydraulic oil is hot.Allow hydraulic oil to cool before removing
any hydraulic fitting.
Wear protective eye covering and gloves.
Lubricating/hydraulic oils used in performa ce of maintenance can be very slippery.
Immediately wipe up any spills.
Failure to follow these warnings may result in injury or death to personnel.
C AU T I O N
Wipe area clean around hydraulic system, and cap all hydraulic hose ends along with
component connections during removal to protect against contamination. Failure to follow
this caution may cause damage to equipment.
The machine ECM sends a PWM signal to a solenoid on hydrostatic motors. When solenoid is activated, hydraulic
fluid is directed to motor, which is attached to final drive, allowing for machine movement. Efficiency of hydrostatic
pumps and motors are essential for machine operation. Refer to WP 0007 for detailed description of hydrostatic
pumps and motors.
This test determines if hydrostatic pumps and motors meet specifications during stall condition. Machine must be
supported and tracks off ground to perform this test (WP 0281).
1. Inspect hydraulic system for Class III leakage and damage. Hydraulic lines must be free from kinks, sharp
bends, and restrictions. Replace if condition found.
2. Turn ignition switch to OFF position (TM 5-2410-240-10).
4. Turn battery disconnect switch to ON position (TM 5-2410-240-10).
5. Turn ignition switch to ON position. Start ET and select machine control ECM.
N OT E
Wait at least 30 seconds for diagnostic codes to become active.
6. Monitor active diagnostic codes with ET. Check and record any active diagnostic codes. If diagnostic codes are
7. Operate machine until hydraulic system oil temperature is at least 104°F ± 9°F (40°C ± 5°C).