The impeller (one) is rotated because of the crankshaft and it converts the mechanical Electricity of the crankshaft into kinetic Power by putting the fluid in movement. Together with the three-passage torque converter, two passages are useful for transmission oil (ATF) movement from the torque converter and for clutch cooling, https://landenbbaxt.blogsvirals.com/33115302/new-step-by-step-map-for-torque-converter-clutch