Along with the a few-passage torque converter, two passages are useful for transmission oil (ATF) stream throughout the torque converter and for clutch cooling, although the 3rd passage is employed independently to manage the lock and unlock with the clutch. A torque converter clutch solenoid is a specialized electromagnetic product https://arthurvvusp.blazingblog.com/34001943/detailed-notes-on-torque-converter-clutch