TM-9-2320-272-10

TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)

TECHNICAL MANUAL; OPERATOR'S MANUAL

SEPTEMBER 2004

CHANGE 2

TM-9-2320-272-10 - Page 362 of 481

TM 9-2320-272-10

Change 2

3-13

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

Table 3-1. Troubleshooting (Contd).

HYDRAULIC CRANE

32. CRANE NOT OPERATING OR LACKS POWER.

Step 1. Check to see if tachometer indicates 1,275 rpm.

If not, pull hand throttle control all the way out.

Step 2. Check to see if transmission selector lever is in 1-5 (drive).

If not, place transmission selector lever in 1-5 (drive).

Step 3. Check to see if transfer case power takeoff lever is pushed back to

engaged position.

If not, push transfer case power takeoff lever back to engaged

position.

Step 4. Check level of hydraulic oil in reservoir (para. 2-24).

If low, add oil to proper level (para. 2-10).

Step 5. Check for hydraulic oil leaks.

Tighten loose connections. If leaks continue, notify unit

maintenance.

33. CRANE DOES NOT LIFT.

Step 1. Check level of hydraulic oil in reservoir (para. 2-24).

If low, add oil to proper level (para. 2-10).

Step 2. Check for hydraulic oil leaks.

Tighten loose connections. If leaks continue, notify unit

maintenance.

34. HYDRAULIC PUMP NOISY.

Check level of hydraulic oil in reservoir (para. 2-24).

If low, add oil to proper level (para. 2-10).

If still noisy, notify unit maintenance.

35. VEHICLE ROLLS WHILE OPERATING CRANE.

Step 1. Check to see if parking brake is applied.

If not, apply parking brake.

Step 2. Check to see if chock blocks are in place.

If not, place chock blocks at wheels and notify unit maintenance.