What are the differences between FWD and RWD transmissions? I mean not just the technical differences, but also the difference in the "behavior" and the feel?

Thank you!

They work exactly the same and in most cases are made of the same components, just one sits sideways. For example, a 4L60 and a 4T60 are the same transmission, except one is a transaxle instead of a transmission, meaning it has the differential built into the trans case.