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 357 of 481

TM 9-2320-272-10

3-8

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

Table 3-1. Troubleshooting (Contd).

8. EXCESSIVE EXHAUST SMOKE AFTER ENGINE REACHES NORMAL OPERATING

TEMPERATURE 175°F TO 200°F (79°C TO 93°C).

Check for restricted air cleaner.

If restricted, clean air cleaner element (para. 3-8).

HEATING SYSTEM

9. HOT WATER PERSONNEL HEATER FAILS TO PRODUCE HEAT AFTER ENGINE

REACHES NORMAL OPERATING TEMPERATURE.

Step 1. Check to see if blower motor switch is in OFF position.

If in OFF position, put blower motor switch in HI or LOW position.

Step 2. Check to see if coolant shutoff valves are closed (para. 2-44).

If closed, open coolant shutoff valves.

Step 3. Check for air in heater.

With engine running, open air bleed drainvalve on engine side of

heater and allow air to escape (para. 2-44). Close drainvalve.

10. HEATER BLOWER MOTOR OPERATES, BUT HEAT FAILS TO REACH CAB, OR

DEFROSTERS FAIL TO OPERATE.

Step 1. Check to see if heat vent control and/or defroster control levers are

adjusted properly.

If not, adjust heat vent control or defroster control levers to direct

heat flow to desired location (para. 2-44).

Step 2. Check to see if heat/defroster vent tubes are connected below

instrument panel.

TRANSMISSION

11. EXCESSIVE CREEP IN FORWARD OR REVERSE RANGE.

Check hand throttle position.

If partially out, push hand throttle all the way in.

12. TRANSMISSION OVERHEATING AS INDICATED BY TRANSMISSION OIL

TEMPERATURE GAUGE.

Check transmission oil level.

If low, add oil (para. 3-10).