[Deakins]

I'm not very good at explainging stuff, so:
http://cssdrivertraining.com/manualprimer.htm - This should answer your first question.
http://www.howstuffworks.com/torque-converter.htm - How torque converters work.
Actually,
http://www.howstuffworks.com/category.htm?cat=sc-engi - How cars work.