i bought my sx a month ago. when I bought it the tranny fluid was really dirty like motor oil colored and over-full. I had the dealership flush the fluid and fix the o2 sensor and now I've noticed it revs high when in park and shifts hard. it doesn't feel like it's slipping but it's not shifting smoothly. this is the first car I've ever bought from a dealer, no warranty, no knowledge, car payment, and a little freaked out. any suggestions? oh, and I don't have a whole lot of money to work with.