With all the 3-passage torque converter, two passages are used for transmission oil (ATF) movement in the torque converter and for clutch cooling, though the 3rd passage is applied independently to control the lock and unlock from the clutch. In modern day automotive programs, it is generally at this stage https://juliusfouzc.aboutyoublog.com/37779853/torque-converter-clutch-fundamentals-explained