Manual Second

Manual Second:

MANUAL SECOND

A Manual 3-2 downshift can be used to provide increased engine braking over Manual Third. This is done by moving the shift selector from the Manual Third position to the Manual Second position. Manual Second can be selected at any vehicle speed or from any gear range and the transmission will downshift into second gear.
- Manual Valve: In the Manual Second range, line pressure which turns into D 21 is directed to the 2-3 shift valve. The manual valve shuts off PRND4 fluid pressure to the Transmission Fluid Pressure Switch ASM and PRND43 fluid pressure to assist the front servo spring. This allows the front band to apply.
- Transmission Fluid Pressure Switch ASM: PRND43 pressure is shut off from the manual valve. This shuts off the electrical signal to the Powertrain Control Module (PCM).
- 1-2 Solenoid: De-energized, exhausting signal "A" pressure through the solenoid allowing spring force to move the 1-2 shift valve to the extreme right.
- 2-3 Solenoid: De:energized, exhausting signal "B" pressure through the solenoid, thus the 2-3 shift valve is forced to the extreme right by spring force and D 21 fluid pressure from the manual valve.
- 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 pressure and D 21 fluid pressure from the manual valve. 2-3 drive pressure from the 1-2 shift valve is changed into Front Band Apply (FBA) and directed to the front servo.
- 3-4 Shift Valve: Held to the extreme right by spring force.
- Front Servo: Front Band Apply (FBA) fluid pressure from the 2-3 shift valve seats the #3 checkball, this causes the fluid to flow through an orifice, into the front servo piston housing which applies the front servo and band.
- 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 in the case 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.
- Overrun Clutch: D321 fluid pressure from the manual valve seats the #1 checkball in the case and causes the fluid to flow through an orifice (which becomes overrun fluid pressure) through the case, pump housing and into the overrun clutch housing which applies the overrun clutch. Thus the overdrive roller clutch becomes ineffective and provides vehicle engine compression braking.