The pump is connected to the motor, and it pumps fluid (normal oil) into the torque converter. The turbine is connected to the gearbox, and it spins in the event the fluid from your pump hits it. A nasty transmission filter will induce your gears to grind on each other https://filter-gearbox63727.thezenweb.com/little-known-facts-about-filter-gearbox-72118561