Anything special about these shafts? A neighbor stopped this morning with a rear driveshaft vibration issue. He took it to a mech. that replaced both ujoints, the vibration is still there. He was told he needs a new shaft due to the "foam" being gone? To me it cant be a whole shaft but I have no experience with Vitara. Any help would be appreciated before I go and look at this thing. Do Tracker shafts interchange? Thanx.