Looks like the Plastic Pan and Filter are 1 Unit. OUCH! $$$$
Sounds like--> Severe Service=35K - 40K Miles Normal Service=60K miles
No other way around it-->If you have plans on keeping this auto for many years to come. Your going to have to spend some $$ to service this transmission--->If you are anal about things you spend a lot of your hard earned $$$ on.
If Not? Just drive it until it quits and leaves you stranded.