TM 5-3895-346-14
TRANSMISSION STARTUP
HYDROSTATIC SYSTEM
TRANSMISSION STARTUP
PROCEDURE
1. After the transmission has been installed, remove the threaded plug from the side of the main pump housing
(refer to Fig. 9, Item A).
For reading charge pressure at this port, install a 600 psi gage, with a short section of hose. The threaded port
is 7/16 x 20 straight thread O-ring. Also install at the charge pump inlet a vacuum gage for reading inlet
vacuum (refer to Fig. 9).
2. Check all fittings to be sure they are tight.
3. When filling any area of the transmission, it is recommended that all fluid be passed through a ten-micron
filter (refer to Fluid Recommendations).
Fill the pump and motor cases through the upper case drain opening with a recommended fluid. Reinstall and
tighten case drain lines.
4. Loosen the charge pump line, coming from the filter/reservoir, at the inlet to the charge pump.
5. Fill the reservoir with fluid. When fluid appears at the loosened hose at the charge pump inlet, install and
tighten the hose and continue filling the reservoir. Leave reservoir cap loose so air will escape.
If gravity feed does not fill the inlet line to the charge pump, it must be filled by hand.
6. It is recommended that the control linkage to the pump control valve be left disconnected until after the
initial startup. This will allow the pump to remain in positive neutral.
7. If the prime mover is:
Engine: (Diesel)
Close the injector rack, turn the engine over until the charge pressure reaches 30 psi or more.
8. Start the prime mover and if possible, maintain a 750 rpm pump shaft speed for 5 minutes. This will allow
the system to fill properly. During this phase, pressure surges may be seen on 600 psi gage. THIS IS
NORMAL.
While running at 750 rpm idle, the pump charge pressure must be at least 100 psi above case pressure. If it is
not, shut down and troubleshoot. (Refer to Troubleshooting.)
9. Increase pump speed to approximately 100 rpm; charge pressure on the 600 psi gage should be 190-210 psi
above pump case pressure. (See Note.)
10. Shut down prime mover and connect linkage to the displacement control valve handle.
CAUTION
If the motor shaft is connected to the drive mechanism, the necessary safety precautions must be considered.
11. Check fluid level in reservoir and add if necessary.
12. Start prime mover and run the pump at 1500 to 1800 rpm; charge pressure should be 190-210 psi above
pump case pressure.
13. Move the pump control handle slowly to the forward and then the reverse position. Charge pressure will
drop to 160-180 psi above motor case pressure.
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