I have done it a couple different ways. One being pull the tranny and just replace the front/rear transmission seals and the other was to pull the tranny and take it to my local, reputable independent where he "re-sealed" it. The re-seal consisted of all the seals in the transmission and ran around $250 for parts and labor.

I would most definitely change the engine rear main while you are in there.

If money allows go ahead and have the driveshaft rebuilt with a new center support bearing, u-joint and balance. Have a reputable driveshaft shop do this job because it is not really a job for a diy'er type.

Clean out the evap drain holes while everything is opened up under there.

Make sure you get the car high enough to allow clearance to get the tranny out from under it and make sure it is secure.

__________________
Jim