Transmission Control Valve - Hitachi ZW180 Technical Manual

COMPONENT OPERATION / Drive Unit

TRANSMISSION CONTROL VALVE

The transmission control valve supplies oil that is
maintained at constant pressure by the regulator valve
to each clutch. This changes vehicle travel direction
and speed.
The transmission control valve is composed of the
valve body and the proportional solenoid valve for
each clutch. It controls the clutch oil pressure by
operating the shift lever, actuating each proportional
solenoid valve, and moving the modulation spool of
the valve body.
The proportional solenoid valve controls oil pressure
according to the electric signals from the controller.
Therefore, the proportional solenoid valve can receive
variety of hydraulic waveforms depending on the
vehicle conditions.
T3-9-28