Driving in reverse gear

After starting off in reverse gear, the PCM turns shift solenoid valve A ON, B and E remain ON, and C and D remain OFF. Shift solenoid valve A pressure (SA) is applied to the right side of shift valve A to cover the A/T clutch pressure control solenoid valve A pressure port, and uncovers the line pressure port leading to the 4th clutch creating full line pressure. The 4th clutch is engaged securely with line pressure.