The only special "tool" I would think you'll need is the ability to
compress the clutch packs to remove/install the retainer snaprings.  I
use a storebought rig that cost about $80.  It has a lever with a
ratcheting pawl to hold the assembly compressed for hands-free
operation.  You could also make an adapter and use it in a hydraulic or
arbor press, or perhaps a large opening vice if you were to be careful.
The springs aren't very strong, but I wouldn't want to try to do it by
hand!

If you have an air compressor, you can use a rubber-tipped blow gun to
check the clutch packs and Low/Intermediate band servo for pressure
leakage.

One thing I've found with the ATX is that every one I've overhauled has
had broken pinnion shafts in the ravigneaux (planetary) gearset.  They
still functioned OK (amazingly), but if you are going to overhaul the
unit, you can get a repaired exchange planetary gearset for pretty
cheap from a trans parts supply house.

Inspect the governor for free spinning and excess loosness in it's
bore.  Then hold it "upside down" at eye level and flop the weight arms
up and down while inspecting the internal valve for movement through
the cast oil passage slots.  Clean the governor thoroughly and operate
the valve gently with a pocket screwdriver through the oil passage
slots afterward to confirm free movement.  There may be only one spring
in only one of the centrifugal weight arms.  It looks weird, but that
is probably the correct calibration for your model from the factory.
Look in the governer mounting hole for another spring.  If you don't
see one, it probably just came with one spring.
Also, there's a common failure part related to the throttle pressure
cable.  I can't remember the specifics, but it is a plastic bushing of
some type that goes on the bellcrank or bracket at the engine.  If it
breaks, your cable will stay fully engaged, and the trans will stay in
1rst gear WAY too long.

If this is a really old ATX, I think circa '84, they used a goofy
centrifugal lock-up torque converter.  Hopefully you have the newer
style with the standard hydraulic converter.  If hydraulic, you may
want to send it to a trans shop to flush out - for peace of mind.
Replace the converter snout bushing in the front support area of the
bellhousing regardless of condition.  Otherwise replace any remaining
bushings and thrust washers that are worn, scored, etc.

Toyota MDT in MO

GOOD!!

It will be that!

Anything can be done given sufficient time and patience.

Lots of them, or lots of ingenuity.  I can't say specifically because
despite having been in the repair field for 36 years and having built
engines, overhauled standard transmissions and built and maintained
circle track race cars I leave automatic tranny overhauls to the
specialists.

Don
www.donsautomotive.com