Mazda 6 Transmission

I have a 2003 Mazda 6. Almost every day, after starting it and driving maybe .10 of a mile, it seems as my car shifts, it shifts really hard, like a thump. I am thinking of having the Transmission serviced. Is this worth it? About what should the cost be? What do they do, just drain the fluid and add new? Thanks for your advice.

For that age of car I would drain and replace the filter. I like dealers for this. That way I know I get the correct fluid. Usually the price isn’t any worse than any place else. Just don’t let them up sell you.

Thank you.