With the 3-passage torque converter, two passages are useful for transmission oil (ATF) flow throughout the torque converter and for clutch cooling, whilst the 3rd passage is applied independently to regulate the lock and unlock of the clutch. The pump section from the torque converter is attached towards the housing. https://franciscopwbde.dsiblogger.com/67267501/facts-about-torque-converter-clutch-revealed