Shifting between 4th Gear and 5th Gear
As the speed of the vehicle reaches the programmed value, the PCM turns shift solenoid valve C ON, and covers the shift solenoid valve C pressure port (SC) to shift valve C. Shift solenoid valves A and B remain OFF. Shift valve C is moved to the left side to switch the line pressure port (4) and the CPC A pressure port (4A) leading to the 4th clutch. Shift valve C also uncovers the CPC B pressure port (4B) leading to the 5th clutch. The PCM actuates A/T clutch pressure control solenoid valves A and B. A/T clutch pressure control solenoid valve A pressure (56) is applied to CPC valve A, and A/T clutch pressure control solenoid valve B pressure (57) is applied to CPC valve B. CPC valve B regulates line pressure (4"), and line pressure (4") becomes CPC B pressure (4B). CPC B pressure (4B) flows to shift valve A via shift valves C and B, and becomes 5th clutch pressure (51) at shift valve A. 4th clutch pressure (40) is changed to CPC pressure, and the 5th clutch is engaged by CPC pressure. The 1st clutch is also engaged, but no power is transmitted because of the one-way clutch.