TM-9-2320-272-23-1
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; FIELD MAINTENANCE MANUAL; VOLUME 1 OF 5
SEPTEMBER 2012
TM-9-2320-272-23-1 - Page 1165 of 1313
FRONT WHEEL DRIVE DOES NOT ENGAGE (FRONT WHEEL DRIVE LOCK-IN SWITCH ENGAGED AND
TRANSFER CASE SHIFT LEVER IN HIGH POSITION) - Continued
STEP
9.
IS THERE AIR PRESSURE IN THE IR LINE AT THE ACTUATOR VALVE DELIVERY PORT?
a.
Stop engine.
b.
Disconnect pressure gauge from vehicle and return air line to original condition.
c.
Disconnect delivery air line from actuator valve delivery port. Refer to point to point schematics.
T0353DAA
DELIVERY
LINE
DELIVERY
PORT
ACTUATOR
VALVE
SUPPLY
LINE
TRANSDUCER
Figure 9.
Actuator Valve.
d.
Connect pressure gauge to actuator valve delivery port.
e.
Start engine and run at idle.
f.
Place transfer case shift lever into low position.
g.
Monitor air pressure on pressure gauge.
h.
After 5 minutes air pressure should read 90 to 130 psi.
CONDITION/INDICATION
IS THERE AIR PRESSURE IN THE AIR LINE AT THE ACTUATOR VALVE DELIVERY PORT?
DECISION
YES - Replace damaged air lines (Volume 5, WP
0805). Go to Step (10) to verify problem is solved.
NO - Notify supervisor. Action may not be possible at this level of maintenance.
TM 9-2320-272-23-1
0140
0140-10
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