I've seen this recently (on a 79 coincidently, but F150). Check all the trans/bellhousing/xfer case bolts. That was the cause of the fluid leaking... Bouncing was 1 (or more) bad tires. We ended up replacing all the tires and it rides like a dream (as well as 79 can) with no leaks. It may not be your problem, but hopefully sharing our experience will help you...
Give me a holler (reply or PM) if you've got any questions.
Later,
JayT
Give me a holler (reply or PM) if you've got any questions.
Later,
JayT