The impeller (one) is rotated by the crankshaft and it converts the mechanical Strength with the crankshaft into kinetic Electrical power by putting the fluid in movement. The TP sensor indicates the throttle plate angle. If the driving force accelerates to huge-open throttle, the TCM disengages the TCC to downshift. https://torque-converter-clutch42973.blogoscience.com/40248298/an-unbiased-view-of-torque-converter-clutch