How often or should you change out Tranny fluid

I change mine every 30k miles. Sounds like your fluid has been in there since 1995 that is a long time. I would drop the pan drain, change filter and replace all the fluid by removing the line that goes into your transmission cooler. You can search here for the details on how to do it. Also you will probably have a magnet in the pan that is covered with filings clean this and the pan well before reassembling.