I t has done this twice at 40 to 60 mph on turns both times......it sounds like just hitting the edge of the rumble bumps.......the first thing that I thought was a failing front ujoint .........I jacked it up and ujoints seemed tight no grease leaks.....bearings and rotors were only slightly warm......wheels tight on hubs.........this never happens just driving around town......just the two times at hiway speeds..........I pulled over both times to make sure nothing was loose or tires tires flat..........turned around both times and headed home at hiway speed with no noise??????.......it has 160000 well maintained miles..........and easy use.........never any other suspension problems