Oh - a torque converter is very much like a jet turbine, but as a fluid clutch. When the fins inside go they can really go. I had one fail on my Escape and it took out the transmission too. But that is its job - push fluid and as a reservoir for a lot of fluid. Most of the fluid you add goes into it. There is also a pump in the motor, but the TC, as the name implies, acts as a clutch to transfer torque from the motor into the transmission. It is designed to slip until RPM spinning it exceeds the internal design to start pushing fluid. This design element changes to adjust the stall (when it engages). Overly simple explanation, but the basic idea, anyway.