Key to hydraulic flow diagram

The flow of fluid up to the 1 – 2, 2 – 3 and 3 – 4 shift valves is the same as in 3rd speed. As the speed of the vehicle reaches a predetermined point, the shift control solenoid valve A is turned off (shift control solenoid valve B remains off). As this occurs, 3 – 4 shift valve is moved to the left and uncovers the oil port leading to the 4th clutch. Since the 1 – 2 and 2 – 3 shift valves are kept on the left side, the fluid flows through the 4th clutch; thereby transmitting power through the 4th clutch.

Line pressure (4) is applied to the 1 – 2 shift valve and 2 – 3 shift valve.

3rd clutch pressure (31) is applied to the 3 – 4 shift valve.

4th clutch pressure (41) is applied to the manual valve.

4th clutch pressure (40) is applied to the 4th clutch.

Hydraulic pressure also flows to the 1st clutch, however, no power is transmitted because of the one – way clutch as in 2nd and 3rd speed.

Key to hydraulic flow diagram