Exactly, You and Matt, ditch_dr, are dead on the money here. Everyone seemed to be saying the same thing. This is a great site for questions like this one. Invariably, someone will have had this problem or have fixed one like it. If we're all giving the same info we're probably at least close to right. I've been a master tech for years and I'm now in charge of a huge fleet of vehicles we've got 20 explorers of various vintages with up to 300,000 miles on them(those ones are real rough). Everyday I try to learn something new, reminds me how much I don't know. I hope we get some feedback as to what fixed this vehicle but it may well be :I got the estimate and decided to live with the vibration. I hope not.