I have a 99 diesel I bought new. It has 153000miles and is a 5 speed. I keep thinking I would like to trade up. I have been looking at 04 to 06 automatics. Most of these rigs have anywhere from 114,000 to 152000. I guess my question is, is it worth the trade up since I already know what I have. It seems like the new technology would be an advantage, plus the automatic. In the year ranges I indicated, which would be the best and is it really worth it. Any words of wisdom would be appreciated.