Ive got an 02 4X4 and am having problems with a vibration at any speed over 60 miles an hour. It does not pull either way, so I'm pretty sure it is not the alignment. I got under it the other day with a mechanic and found that the first u-joint coming out of the left side of the front differential is a bit loose. Enough so that I can move the unit considerably up and down. I am fairly unfamiliar with IFS, as I've owned jeeps my whole life. The part is cheap to replace, but how easy of a fix is it? Is there anything more to it than compressing the unit, removing the splines from the diff, and replacing it? The mechanic said something about being out of adjustment from the beginning. Let me know if anyone has had this same issue. thanks.