Overdrive Range Second Gear

Overdrive Range - Second Gear:

OVERDRIVE RANGE 2nd. GEAR

To obtain second gear, the Powertrain Control Module (PCM) receives input signals from the Vehicle Speed Sensor (VSS), Throttle Position Sensor (TPS) and other engine sensors, to determine when to "de-energize" solenoid "A".
^ Manual Valve: In the Overdrive range second gear, line pressure from the pressure regulator valve is directed as PRND4, PRND43 and Drive fluid pressures. The PRND4 fluid pressure is directed to the Pressure Switch Manifold (PSM) and to the 2.3 shift valve, the PRND43 fluid pressure is directed to the PSM and to the front servo, and the Drive fluid pressure is directed to the PSM and forward clutch.
^ Pressure Switch Manifold (PSM): Drive, PRND and PRND43 fluid pressures from the manual valve are directed to the DR, PRND4 and PRND43 switches on the PSM, this sends a signal to the PCM that the transmission is in Overdrive range.
^ Solenoid "A": De-energized, exhausting signal "A" fluid thru the solenoid allowing spring force to move the 1-2 shift valve to the extreme right.
^ Solenoid "B": De-energized, exhausting signal "B" fluid thru the solenoid, thus the 2-3 shift valve is held to the extreme right by spring force.
^ 1-2 Shift Valve: Is held to the extreme right by spring force. Drive fluid pressure from the manual valve is changed into 2-3 drive fluid pressure at the 1-2 shift valve, this pressure is directed to the 2-3 shift valve, Pulse Width Modulated (PWM) solenoid and the intermediate (second) clutch.
^ 2-3 Shift Valve: Is held to the extreme right by spring force. 2-3 drive fluid pressure from the 1-2 shift valve is changed into Front Band Apply (FBA) and directed to the front servo. PRND4 fluid pressure from the manual valve is held at the 2-3 shift valve to be utilized in other gear ranges.
^ 3-4 Shift Valve: Held to the extreme right by spring force.
^ Forward Clutch: Is applied by Drive fluid pressure from the manual valve.
^ Intermediate (Second) Clutch: Is applied by 2nd fluid pressure from the 1-2 shift valve. 2-3 drive fluid pressure from the 1-2 shift valve seats the #4 checkball and causes the fluid to flow through two orifices (which then becomes 2nd apply fluid pressure) into the center support which applies the intermediate (second) clutch.