Overdrive Range Third Gear (Torque Converter Clutch Applied)

Overdrive Range - Third Gear (TCC Applied):

OVERDRIVE RANGE THIRD GEAR (Torque Converter Clutch Applied)

To obtain third gear, the Powertrain Control Module (PCM) receives input signals from the Vehicle Speed Sensor (VSS), Throttle Position Sensor (TP Sensor) and other engine sensors, to determine when to "energize" solenoid "B".
- Manual Valve: In the Overdrive range third 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 Transmission Fluid Pressure Switch ASM and to the 2-3 shift valve, the PRND43 fluid is directed to the Transmission Fluid Pressure Switch ASM and to the front servo, and the Drive fluid is directed to the Transmission Fluid Pressure Switch ASM and forward clutch.
- Transmission Fluid Pressure Switch ASM: Drive, PRND4 and PRND43 fluid pressures from the manual valve are directed to the DR, PRND4 and PRND43 switches on the Transmission Fluid Pressure Switch ASM, this sends a signal to the PCM that the transmission is in Overdrive range.
- 1-2 Solenoid: De-energized, exhausting signal "A" pressure through the solenoid allowing spring force to move the 3-4 shift valve to the extreme right.
- 2-3 Solenoid: Energized, the signal "B" pressure with spring force holds the 1-2 shift valve to the extreme right.
- 1-2 Shift Valve: Held to the extreme right by signal "B" fluid pressure and 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: PRND4 fluid pressure from the manual valve is directed through the 2-3 shift valve (which turns into 4TH CL FD fluid pressure) to the 3-4 shift valve. 2-3 DR fluid pressure from the 1-2 shift valve is changed into 3RD CL FD 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. 3RD CL FD 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 direct clutch.
- 3-4 Shift Valve: 4TH CL FD fluid pressure is blocked at the 3-4 shift valve to be utilized in Overdrive range fourth gear.
- 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 clutch.
- Direct Clutch: Third/reverse pressure from the #11 checkball flows through the case and the center support to apply the inner piston area of the direct clutch.
- Third Clutch Accumulator: 3RD CL fluid 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 fluid pressure.
- Pulse Width Modulated (PWM) Solenoid: When energized by the PCM signal pressure shifts the converter clutch shift valve, thus the Torque Converter Clutch (TCC) is applied. The signal pressure also acts on the torque converter clutch regulator valve which regulates output pressure to control the apply and release of the TCC.