Shifting between 2nd Gear and 3rd 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 ON. Shift valve C is moved to the left side to switch the line pressure port (4) and CPC A pressure (4A) leading to the 2nd clutch. Shift valve C also uncovers the CPC B pressure port (4B) leading to the 3rd 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 flows to shift valve A via shift valves C and B, and becomes 3rd clutch pressure (30) at shift valve A. 2nd clutch pressure (20) is changed to CPC pressure mode, and the 3rd clutch is engaged by CPC pressure. The 1st clutch is also engaged, but no power is transmitted because of the one-way clutch.