My Honda Accord has an automatic transmission. When I put my car in reverse to pull out of our driveway which is slightly downhill, the car will move a little, them there is a bump sound and then it continues in reverse. It sounds like I ran over something, but I haven't. I'm thinking it has something to do with the transmission and I am hoping it is not to costly to repair. Thanks.

If you haven't had your transmission fluid changed in the last 24,000 miles or 2 years, I'd recommend that it be done. This is the main thing a car owner can do to protect one of the most problematic components in a car.