What to do on transmission that is off anyway

1990 Ford Taurus 3.01L V6 automatic 75k. My mechanic is dropping the transmission to replace a flex plate/ring gear. That being the case, and since the transmission is losing about 1 to 2 cups of fluid between 3,000 mile oil changes, what things on the transmission, besides whatever is needed to stop the leak, should be done on a do-it-when-it’s-off-anyway basis? I don’t mind spending a couple hundred or so to use the chance.

The front pump seal (a.k.a. torque converter seal) and engine rear main seal should always be replaced even if neither one is leaking. Those seals are about 20ish years old and aged rubber.
Murphy’s Law says that if you don’t change them they will leak next week; both of them.

Unless you’re going to authorize a rebuild, all you really can do is a fluid change and replace seals. I’d definitely replace all the seals and gaskets, including the rear main seal on the engine, the front pump seal on the transmission, and the two axle seals on the side of the transmission. I don’t know if this transmission uses solenoids to control the lock-up function and/or overdrive, but having those looked at couldn’t hurt.

This site works because of help from folks like you. Thanks for the answers.

Rubber. It is the bain of my existance. I have replaced almost every piece of rubber on a 2001 ford focus - and the last things - like the radiator hoses, are now starting to blow out. I only got 4 more hoses and a timing belt before I will have pretty darned close to 100% new rubber. well, some polyurathane, but its not old cracking rubber.

If its rubber - and its more than 10 years old, its GETTING THERER. I would also be looking at all of the hoses going to / from the transmission as well as radiator hoses as well as getting that timing belt replaced.

Also check fittings for the transmission. Sometimes they rust. Then crack. Then you lose all transmission fluid in about 30 seconds. Then your transmission dies. Ford focus has one really bad one of these. Yours may or may not.

Check the mount while it is so accessible. But absolutely, as mentioned above, the seals should be replaced.