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 351 of 481
TM 9-2320-272-10
3-2
MALFUNCTION
NO.
MALFUNCTION
TROUBLESHOOTING
PROCEDURE
PAGE
3-4. TROUBLESHOOTING SYMPTOM INDEX
ENGINE
1.
When starter switch is turned to start, engine fails to crank . . . . . . . . . 3-5
2.
Engine cranks but does not start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
3.
Engine cranks but fails to start at outside temperatures
below +32°F (0°C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
4.
Engine starts but misfires, runs rough, or lacks power . . . . . . . . . . . . . . 3-6
5.
Engine overheats as indicated by engine coolant
temperature gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
6.
Low engine oil pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
7.
Engine failure during operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
8.
Excessive exhaust smoke after engine reaches normal operating
temperature 175°F to 200°F (79°C to 93°C) . . . . . . . . . . . . . . . . . . . . . . . . 3-8
HEATING SYSTEM
9.
Hot water personnel heater fails to produce heat after
engine reaches normal operating temperature . . . . . . . . . . . . . . . . . . . . . 3-8
10.
Heater blower motor operates, but heat fails to reach cab, or
defrosters fail to operate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
TRANSMISSION
11.
Excessive creep in forward or reverse range . . . . . . . . . . . . . . . . . . . . . . . 3-8
12.
Transmission overheating as indicated by transmission oil
temperature gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
Section II. TROUBLESHOOTING PROCEDURES
3-2. SCOPE
3-3. TROUBLESHOOTING PROCEDURES
The troubleshooting table contains instructions that will help the operator identify
and correct simple vehicle malfunctions during operations. The table also helps the
operator identify major mechanical difficulties that must be referred to unit
maintenance.
NOTE
Operators should perform the corrective action in the
order listed.
This manual cannot list all malfunctions that may occur. If a malfunction occurs
that is not listed in table 3-1, notify unit maintenance.
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