TM 9-2320-272-24-l
l-20. 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/Al/A2, M932/A1/A2, and M936/A1/A2 vehicles.
Major components of the transmission control system are:
Item and Function
Key
TRANSMISSION SELECTOR LEVER - Is used to select vehicle driving gear range.
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PTO CONTROL LEVER - Engages transmission power takeoff to provide power for auxiliary
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equipment.
TRANSMISSION CONTROL SWITCH - Actuates transmission lockup solenoid valve when
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transmission selector lever is placed in NEUTRAL and transfer case shift lever lockout switch is
pressed.
TRANSMISSION NEUTRAL START SWITCH - The neutral start switch, wired to the starter
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switch, prevents the engine from being started with transmission in gear.
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switch and transfer case switch, the 5th-gear lockup solenoid valve directs main oil pressure of
transmission to the transmission governor system. This puts transmission in 5th-gear, creating less
drag on transfer case synchronizer which permits smoother shifting from one transfer case drive
range to another. Refer to para. l-20f, Transfer Case Control System Operation, for further details.
TRANSMISSION PTO - Driven by the transmission, the PTO drives the hydraulic pump which
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provides hydraulic pressure to power the front winch on M925/A1/A2, M928/Al/A2, M930/Al/A2,
M932/Al/A2, and M936/A1/A2 vehicles, and to power the dump body on M929/A1/A2 and
M930/Al/A2 vehicles. The PTO is mounted on the right front side of the transmission.
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