Pillage around. The AW4 was used in XJ, MJ, 1993 ZJ, and (I think) some YJ/TJ. It was also used by Toyota (it's their design) in the pickup, RWD van, and some RWD cars. It may also be in 4Runner - but I'm not sure - and some Lexus. I think Toyota called it an A03-40 (or something similar
but the point I'm making is that it's a popular box, comparable in available to the THM350/400 and C-4/5/6 - probably the A727 as well.
I know there are some outfits that deal with "performance upgrades" for the AW4 (like Level Ten -
www.levelten.com, I think,) so they probably handle overhauls as well.
I've also heard that the AW4 doesn't take too well to home rebuilds, but no-one seems to have told that to my 1989 Limited - I overhauled that box about 60Kmiles ago without incident (or my 1987 Pioneer - I did that one about 90K ago.)
The AW4 is a simple box - no bands! - but it wasn't my first slushbox to rebuild either, so that might have something to do with it. If you're game, the ATSG service/overhaul manual is floating around, and I might have a copy myself. Getting an AW4 out of a rollover and having it overhauled might be an option for you - the bellhousing and transfer case adapter are both removable (but make sure you get a 4WD version, since the mainshafts are different.) The central case is the same on every version, so you can swap the bell and adapter without worry.
If I just wanted to get the thing running, I'd probably buy a low-miler, drop the valve body and clean it (varnish and crud does tend to build up in there) and re-seal the thing - a gasket, seal, check ball, and filter kit for the thing should run you less than $100. You'll have extra valve body gaskets when you're done - just toss them (there are about four different valve body versions - but the seals and the rest of the gaskets are all the same.) Be sure to take a picture of the check ball locations
before you remove anything! Probably no need to disturb the clutches and gearsets - the only reason I did was because I'd done loads of slushboxes before, but I hadn't seen the inside of an AW4 yet (and I went and bought a $50 core that turned out to be buildable, so I did.) Ended up going through the whole thing - and I made all the "special tools" they said I needed for about $15 worth of shop scrap and hardware store material.
Out of all the automatics I've been through, the AW4 was probably the simplest.
