It's not uncharted territory.
From NAXJA:
The AW4 is a fairly simple box - and a "Master" rebuild kit (including clutches, steels, and whatever) goes for about $300 locally, or a "Overhaul" kit (basically a reseal kit and components to renew the valve body) for about $90 - both at the tranny shop up the street from me here.
You will need two "special" tools that I was able to make from bulk stock - there are some very large snap rings (which won't work with standard snapring pliers - I made a part of "chopsticks" using 1/4" aluminum round rod and D&T for #4-40 setscrews) that worked well, and get a decent bit of barstock and some M10x1.5 and M8-something (I don't remember what) and some 1/2-20 allthread to make the bridge puller to pull the planetary sets out. If you need me to, I can probably dig them up and take digipix for you sometime in the next couple days.
Total cost for "special" tools - about $20, all up.
You MUST have a camera capable of giving you pictures straight away for any valve body work - since there seem to be a few revisions of what goes where, and the manual isn't always right. I should have the ATSG AW4 manual around here somewhere as a .pdf (it's the one I used - and I found it online somewhere. Probably at Strokers - groups.yahoo.com/group/strokers) which has everything else correct - I've just never trusted manual pix of valve bodies (and I'm usually rewarded for that lack of trust.)
The three valve body solenoids can be readily checked with an ohmmeter - as I recall, 13 +-3 ohms is nominal. Hopefully, they're fine - they're spendy to replace (and I haven't been able to build up a stock.)
With either renewal kit, you WILL have valve body gaskets left over - it's a kit for all AW4 variants (Celica, Supra, Pickup, Van, XJ, MJ, ...) and you will match the gaskets up against the old ones to select them.
Here's a more detailed how-to:
http://www.fourwheeler.com/how-to/t...-4-four-speed-automatic-transmission-rebuild/
