Leaking Driveshaft...HELP!!!

Welp, there's one thing I can trust about my '66 Barracuda: that when one thing gets fixed, another thing breaks! :banghead:

And since I don't know squat about transmissions, I need some help on this one! Went out to take her out this morning to discover a giant puddle (could be an understatement - maybe "pond" is the right word) of tranny fluid leaking from the driveshaft right under where about the drivers seat is. Apparently this all happened overnight too. I'm including pictures so you can see where it is dripping from. Like I said, I don't know much about transmissions so I could use some help diagnosing this one!

273 Engine, Automatic 3-Speed Transmission!