I recently bought my second explorer. I used to have a 98 with the 5.0 and 4wd. I bought a 98 sport today. I like it a lot, but I am a little upset it is not 4wd. Do they make 4wd sports? If so is it at all possible to make mine a 4wd. Also how do I know what engine size i have. I know it is a 4.0 v6, but the are three sizes. 4.0l/254, 4.0l/244, and 4.0l/242. Also my exhaust or muffler is shaking some times. What is going on?