Not very - I've been thru a couple (and Beez has been inside one or two.) If we can figure it out, so can you.
Make sure to get teh ATSG AW4 manual from the strokers group (groups.yahoo.com/group/strokers, files section) and take a picture of the valve body if/when you split the halves. There are a few different check ball locations, and the pix in the FSM and the ATSG book are wrong!
Expect a reseal kit to go for about $90, a Master kit (includes friction and such) for about $250-300, and there are a couple bridge pullers you might need that can be made from bar stock and allthread (metric, of course. It's a Toyota design!)
You probably won't need the friction kit, the clutches in the AW4 are pretty hefty. You will probably want to tear it down before you order the kit to be safe, tho...
WHen you order the kit, be sure to specify it is in a Jeep - especially if you need friction. The AW4 was also used in the Toyota Celica, Supra, Van, and Pickup.
5-90