The impeller (one) is rotated via the crankshaft and it converts the mechanical Electrical power on the crankshaft into kinetic Power by putting the fluid in movement. With the a few-passage torque converter, two passages are used for transmission oil (ATF) stream through the torque converter and for clutch cooling, https://torqueconverterclutch07529.mybuzzblog.com/13694337/the-basic-principles-of-torque-converter-clutch