Manual Third (Torque Converter Clutch Applied)

Manual Third (TCC On):

MANUAL THIRD (TCC ON)

Manual 3rd can be used to increase the performance of the vehicle by allowing higher engine RPMs for more torque. Manual Third will also provide vehicle engine compression braking when descending slight grades. Manual third can be selected at any vehicle speed. The transmission will downshift into third gear at any vehicle speed.

- Manual Valve: In Manual Third range, line pressure from the pressure regulator valve is converted into PRND43, Drive and D321 pressures. The PRND43 pressure is directed to the pressure switch manifold and front servo, the Drive fluid pressure is directed to the forward clutch, and the D321 fluid pressure is directed to the #1 checkball and overrun clutch.
- Pressure Switch Manifold (PSM): PRND43 and Drive fluid pressure from the manual valve is directed to the PRND43 switch and DR switch on the PSM, this sends a signal to the Powertrain Control Module (PCM) that the transmission is in manual third.
- Solenoid "A": De-energized, exhausting signal "A" pressure thru the solenoid allowing spring pressure to move the 3-4 shift valve to the extreme right.
- Solenoid "B": Energized, the signal "B" fluid pressure moves the 2-3 shift valve against the spring force to the extreme left.
- 1-2 Shift Valve: Held to the extreme right by signal "B" fluid and spring pressure. 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 Motor (PWM) solenoid and the intermediate (second) clutch.
- 2-3 Shift Valve: 2-3 fluid pressure from the 1-2 shift valve is changed into 3CLFD fluid pressure at the 2-3 shift valve, this fluid is directed to the #8 checkball which seats and forces the fluid through an orifice (where it becomes 3RD CL fluid pressure) and is directed to the third accumulator. 3CLFD fluid pressure is also directed to the #11 checkball which seats and forces the fluid through an orifice (which changes into 3RD REV fluid pressure) and to the third clutch.
- Rear Servo: 2nd fluid pressure is supplied to the rear servo in the same manner as it is to the 2nd clutch. This fluid pressure is directed to the inner piston of the rear servo, thus applying the inner piston.
- Front Servo: PRND43 fluid pressure from the manual valve is directed to the front servo which assists the spring with holding the front servo off.
- Overrun Clutch: D 321 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.
- Forward Clutch: Is applied by Drive fluid pressure from the manual valve.
- Direct Clutch: Third reverse pressure from the #11 checkball flows through the case and into the center support to apply the inner piston area of the direct clutch.
- 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.
- Third Clutch Accumulator: Third clutch pressure is also applied to the third clutch accumulator which is encased in the accumulator housing. This moves the third accumulator piston against the spring force and accumulator pressure which smooths the 2-3 shift.
- Pulse Width Modulated (PWM) Solenoid: When energized by the PCM signal pressure shifts the converter clutch shift valve, thus the [1][2]Torque Converter Clutch (TCC) is applied. The signal pressure also acts on the Torque Converter Clutch Regulator valve (TCCR) which regulates output pressure to control the apply and release of the TCC.