TM 9-2320-272-10
1-17.
CONTROL SYSTEM OPERATION (Contd)
e.
Transmission Control System Operation.
The transmission control system permits shifting of transmission, prevents starting of engine with transmission in
gear, and prevents shifting of transfer case unless transmission is in neutral. This system also permits engagement of the
Transmission Power Takeoff (PTO) to provide hydraulic power for auxiliary equipment on M925/A1/A2, M928/A1/A2,
M929/A1/A2, M930/A1/A2, M932/A1/A2 and M936/A1/A2 vehicles. Major components of the transmission control system
are:
L
TRANSMISSION SELECTOR LEVER - Is used to select vehicle driving gear range.
M
POWER TAKEOFF CONTROL LEVER - Engages transmission power takeoff to provide power for auxiliary
equipment.
N
TRANSMISSION CONTROL SWITCH - Actuates transmission lock-up solenoid valve when transmission
selector lever is placed in neutral and transfer case shift lever lock-out switch is pressed.
O
TRANSMISSION NEUTRAL START SWITCH - The neutral start switch, wired to the starter switch, prevents
the engine from being started with transmission in gear.
P
TRANSMISSION 5TH-GEAR LOCKUP SOLENOID VALVE - Activated by transmission control switch and
transfer case switch, the 5th-gear lockup solenoid valve directs main oil pressure of transmission to the
transmission governor system. This puts the transmission in 5th-gear, creating less drag on the transfer
case synchronizer which permits smoother shifting from one transfer case drive range to another. Refer to
paragraph 1-17f, Transfer Case Control System Operation, for further details.
Q
TRANSMISSION POWER TAKEOFF (PTO) - Driven by the transmission, the PTO drives the hydraulic pump
which provides hydraulic pressure to power the front winch on M925/A1/A2, M928/A1/A2, M930/A1/A2,
M932/A1/A2, and M936/A1/A2 vehicles, and to power the dump body on M929/AVA2 and M930/A1/A2
vehicles. The PTO is mounted on the right front side of the transmission.
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