The torque converter clutch applies during Third gear operation after the PCM receives appropriate input signals from the VS Sensor, the TP Sensor, and the engine temperature sensor. When the proper vehicle operation conditions have been met, the ON/OFF converter clutch solenoid (315) is energized (turned ON). In some models the pulse width modulated (PWM) solenoid valve (325) is also energized. The PWM duty cycle is ramped between 0 and 100 degees in order to regulate the PWM fluid pressure to the converter clutch regulator valve (330). Regulated applied pressure is then sent to the converter clutch valve (335) into the applied passage. Applied fluid seats the #1 checkball (372) against release fluid and the applied fluid sets the converter clutch. Applied fluid is also present at the torque converter blow-off valve (417-420) in order to exhaust excess fluid pressure. Converter feed fluid at the converter clutch valve (335) is allowed to feed into the cooler passage, through the cooler check valve (28), through the cooler, and into the lube system of the transmission.

The PWM solenoid valve is controlled by the PCM. The solenoid modifies the PWM duty cycle in order to vary the feed pressure in the PWM fluid passage to the convert clutch regulator valve (330). This arrangement provides for accurate control of the regulated converter clutch applied (and released) pressure.

The converter clutch regulator valve provides regulated applied fluid to the converter clutch valve (335) into the applied fluid passage.

When the converter clutch solenoid is energized (turned ON), TCC signal fluid shifts the converter clutch valve (335) against spring pressure.

When the converter clutch valve is shifted, the valve performs the following tasks:

The #1 checkball is located in the channel plate (400). The checkball blocks release fluid while sending applied fluid to the torque converter clutch blow-off valve (417-420).

The cooler check valve allows cooler fluid to pass through the cooler and to provide lubrication for the transmission. The valve also prevents converter drainback when the engine is turned off.