I'm not much of a michanic but my '04 Silverado is coming up on 100k miles so I want to do a tune up or have someone do it for me. Anyways what are some things I need to get done? Should I get a transmission flush? Its never been done and I hear it could mess some stuff up. I don't do a lot of towing so... Also how about the coolant system? Does it needs flushing too? What belts do I need changed? Anything else other then the usual spark plugs and wries? Thanks in advance.