The impeller (one) is rotated via the crankshaft and it converts the mechanical Electrical power from the crankshaft into kinetic Power by putting the fluid in movement. Together with the three-passage torque converter, two passages are used for transmission oil (ATF) move through the torque converter and for clutch cooling, https://torque-converter-clutch25781.izrablog.com/34486294/not-known-facts-about-torque-converter-clutch