Too bad you aren't near, they are actually very simple to tear down and reassemble, at least for me after doing a few. Pull the pan and check for the obvious: clutch material, metal pieces, and burnt fluid. If none of those exist you will probably be ok.
What's been stated so far is good. There is a set of 'air' tests you can run but you have to have an AOD 'test plate'. They run about $130 or you can make one. You can still test a few of the clutches without it if you have a rubber-tipped air gun.
As far as the driveshaft? The AOD requires a 1" shorter yoke. If you are thinking about keeping the C4 around then go to a junkyard and get and AOD yoke. Otherwise you might have to cut the last 1" off of it. TEST FIT yours first.
The conversion kit that CJ Pony parts offers comes with a new yoke I suspect that is probably why. The tranny was in a fox running 11s on a big shot of NO2. It has a fairly new Dayco 3500 stall non lockup. Still has the shifter cable and TV cable attatched.