The impeller (one) is rotated from the crankshaft and it converts the mechanical Vitality of the crankshaft into kinetic energy by putting the fluid in movement. The stator sends the fluid getting back from the turbine on the pump. This enhances the performance from the torque converter. Note the spline, https://torqueconverterclutch74063.glifeblog.com/33196767/torque-converter-clutch-an-overview