I have noticed the same thing in my 93 Trooper. My friend at school had the same problem with his 93 Trooper as well (We had the same model,same options and everything, just opposite color schemes). We used to have the same size tires which 245's, but I've gone up to a 265 now and I noticed a decrease in the amount of vibration I get when I'm decelerating from the same speeds. Maybe by putting the larger size on it absorbs the vibration more, I don't know <img src="/forums/images/graemlins/confused.gif" alt="" />. I'd like to know what causes this as well. The only thing that I can think of is that the trooper is so dang heavy that when it slows down at such high speeds,strains the tranny. My .02, I'm probably way off the mark, but gotta toss an idea out there <img src="/forums/images/graemlins/shiner.gif" alt="" />