TM 9-2320-272-24-2
Table 4-1. Mechanical Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 10. Check hydraulic oil temperature.
a. If oil temperature is greater than 32F (0C), proceed to step 11.
b. If oil temperature is 32F (0C) or cooler, start engine (TM 9-2320-272-10), engage crane
hydraulic system (TM 9-2320-272-10), and allow oil to circulate for 15 minutes.
Step 11. Check boom relief pressure and flow. Start engine and engage crane hydraulic system
(TM 9-2320-272-10). Ensure boom is secured in travel position and fully retracted. Move
crown lever to the retract position. Record flow and pressure readings. Shut down engine.
Proper flow rate is 65 gpm (246 Lpm) or greater. Proper boom relief pressure is 1,325-
1,375 psi (9,136-9,480 kPa).
a. If readings are normal, proceed to steps 16 and 17.
b. If pressure is 1,500 psi (10,343 kPa) or less, and flow rate is less than 65 gpm
(246 Lpm), proceed to step 12.
c. If pressure is greater than 1,500 psi (10,343 kPa), proceed to step 14.
d. If pressure is greater than 1,325 psi (9,136 kPa), and flow rate is 65 gpm (246 Lpm) or
greater, proceed to step 15.
e. If pressure is normal, and flow rate is 65 gpm (246 Lpm) or greater, perform
malfunctions 56 through 59.
Step 12. Check pump suction line for restrictions.
a. If pump suction line is not restricted, proceed to step 13.
b. If pump suction line is restricted, clear restrictions. Check boom relief pressure and flow
rate (step 11).
Step 13. Check air pressure being delivered to transmission 5th gear lockup pressure switch.
a Remove hose assembly (21) from tee (22).
b. Install appropriate hose (20), reducer (23), and pressure gauge (Appendix E, Item 168) (16)
on tee (22).
c. Start engine, place transfer case in neutral, and engage transfer case PTO
(TM 9-2320-272-10). Record pressure.
d. If no air pressure is being delivered to pressure switch, inspect air lines for restrictions
or leaks. If air lines are restricted or have leaks, clear restrictions or repair leaks
(TM 9-243). Recheck boom relief pressure (step 11).
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