-do a transmission filter and fluid change
You might not want to do that, if it's never been done, all of that crud in there might be holding your transmission together hah. You might change it and your transmission fails not too long after. Unless you have the service records, it's better off not to touch it in my opinion. I've seen way too many transmissions fail after a flush or fluid change.
My grandfather was a transmission mechanic for 45+ years and really tried to talk a lot of customers out of doing it on old cars with no service records, or high mileage cars. If you aren't having any problems with it, don't try to fix what isint broken. If you are having problems, there's a chance it'll just make it worse.