Not positive what you're describing...directly after the transmission IS the transfercase. You spun your disconnected front driveshaft? What end was disconnected? The end that attaches to the front differential?
If you cracked what your transmission connects to, you either cracked your engine or your transfercase. Must give you the benefit of the doubt and say you know what the engine is, so you cracked your transfer case, and so you are losing t-case oil. Unless there's somehow something different with a V6 engine...A photo would help.
If you cracked your transfercase you can remove it without removing the transmission. You just place a jack under the transmission and lift it slightly, take off all the bolts that connect it to the t-case, remove rear driveshaft, take off the crossmember, drop t-case. Also some wires and (maybe?) the speedometer cable.
Just don't ever drain the tranny fluid until you get that fill plug figured out! A shop could get it off, but I know people here have methods for you, too.
