Where in a transmission is the fluid pump? How much does it cost to replace it?

What is your question?

All of a sudden when I cranked my Mighty Max up one day, it sounded strange. When I put it into drive (auto transmission) it started roaring before it would finally shift. It did this in every gear. After the first couple of miles it would not move at all, except barely in reverse. Soon it stopped and wouldn't move at all. Had to call a friend to tow me back home. He said it sounded like the pump that pumps transmission fluid thru the transmission was going or gone. I have never heard of this problem, but I don't know a lot about transmissions.