Actually, it is not to hard to do, and you don’t need any special tools, other than a slide hammer, and maybe a seal driver if you want/need to replace the output shaft bearing (it is somewhat like a cam bearing, but longer).
Get a good kit with heavy duty clutches, bands, and it should have all the gaskets and seals you need. The directions are straight forward, easy to follow. There is an emphasis on clean,clean,clean... I used an old white sheet on my garage floor, to lay everything out.
Whether you do it yourself or not, this is a good time to upgrade to a performance valve body, which really changes the personality of the trans. Also, a higher ratio “band apply lever” and accumulator spring(read up on these, and make your choice).
Go for it. Basically:
you drop the valve body,
pull the front pump assembly, pull the guts out the front,
the clutch discs are held in the guts by a snap ring,
Replace the clutch plates,
Remove and replace the bands,
Replace the apply lever,accumulator spring, if upgrading.
Replace the seal where the valve body shifter comes through the case
Replace front and rear seals,
Put the guts back in, adjust the bands according to the directions (inch pound wrench needed)
Replace valve body, gasket & pan,
Spend the $800 you just saved on something else!
SMR Transmission has a good kit for $263. Includes severe duty Raybestos clutches and Kick down band.
smrtrans.tripod.com