Transmission shifting funny.
I have a 98 740iL. I bought it 3 1/2 years ago with 134k on it. It has been a great car. Recently I notice when I'm at speed say 45 to 65 it seems to be shifting up and down very slightly and I can see the RPM shift up and down maybe 100 to 200 RPM. I was going to try a fluid and filter change. Anybody give me some advise please? I'm going to be taking a 1600mi roadtrip mid April and don't want to be walking.