The components of the torque converter lockup control circuit are the torque converter lockup switch, the electronic transmission control, the lockup clutch solenoid, the engine speed sensor and the transmission speed sensor.
(1) Torque converter lockup switch
(2) Electronic transmission control
View of torque converter
(3) Lockup clutch solenoid
Rear view of engine
(4) Engine speed sensor
View of transmission
(5) Transmission speed sensor
With the key start switch in the ON position, 24 volt is supplied from the batteries via circuit breaker #9 to the electronic transmission control.
With the engine running, engine speed sensor (4) and transmission speed sensor (5) generate a signal that is sent to electronic transmission control (2). The electronic transmission control monitors the engine speed signal and the transmission speed signal. With the two signals the electronic transmission control calculates the torque converter rpm.
The electronic transmission control provides 24 volt power to torque converter lockup switch (1). When the lockup clutch switch is in the ON position a ground circuit to provided for the electronic transmission control.
With the torque converter lockup switch in the ON position, the electronic transmission control supplies 24 volt power to energize lockup clutch solenoid (3). The electronic transmission control applies 24 volt power to the lockup clutch solenoid when the following conditions are met.
- Torque converter lockup switch is in the ON position.
- Torque converter rpm is within a preset value.
- The machine has been operated in the current speed and direction for at least 0.8 seconds.
- A minimum of 4 seconds has passed since the lockup solenoid was deactivated.
- Presently selected gear is F2 to F4 or R1 to R4.
The lockup clutch will be disengaged when:
- Torque converter lockup switch is moved to the OFF position.
- Torque converter rpm moves out of the preset value.
- A transmission gear shift is activated.
Torque converter lock up control circuit