Overrun Clutch Control Valve Operation
When the solenoid valve is "ON", pilot pressure is applied to the overrun clutch control valve. This pushes up the overrun clutch control valve. The line pressure is then shut off so that the clutch does not engage. Only in "1" position, however, 1 range pressure is applied to overrun clutch control valve, resulting in valve moving downward and clutch engaged.
When the solenoid valve is "OFF", pilot pressure is not generated. At this point, the overrun clutch control valve moves downward by spring force. As a result, overrun clutch operation pressure is provided by the overrun clutch reducing valve. At overrun clutch reducing valve in "D" position, the hydraulic pressure is reduced to a level that balances the spring force. This is sent to overrun clutch control valve and becomes the operating pressure of overrun clutch which is engaged at all times. In "2" position and "1" position, overrun clutch reducing valve is pushed down by 2 range pressure. Line pressure is directly sent to overrun clutch control valve and becomes the operating pressure of overrun clutch which is engaged at all times.