Shifting between 1st Gear and 2nd Gear
As the speed of the vehicle reaches the programmed value, the PCM turns shift solenoid valve A ON, and uncovers the shift solenoid valve A pressure port (SA) to shift valve A. Shift solenoid valves B and C remain ON. Shift valve A is moved to the right side to uncover the CPC A pressure port (4A) leading to the 2nd clutch. The PCM actuates A/T clutch pressure control solenoid valve A. A/T clutch pressure control solenoid valve A pressure (56) is applied to CPC valve A. CPC valve A regulates line pressure (4), and line pressure (4) becomes CPC A pressure (4A). CPC A pressure (4A) flows to shift valve B via shift valves C and A, and becomes 2nd clutch pressure (20) at shift valve B. The 2nd clutch is engaged by CPC pressure. The 1st clutch is also engaged, but no power is transmitted because of the one-way clutch.