So I am there. It's 99.9% done. I have all four engine/tranny mount bolts out. But I lower it all down a couple inches, take a look around everything and see this:

I have a 74 tranny with the speedo cable that's connected right at the back of it. None of the books, write-ups, or tech articles I've read go over this type of connection.
To the experts: How do I disconnect this cable? Do I unscrew the big nut that the cable is apparently going into? Is tranny fluid going to come pouring out when I do? This is the only thing keeping me from being able to lower the engine to the ground, any help would be greatly appreciated! Thanks!!