Re: 2001 windstar rear of van vibrates @ hi speed
You can easily check for bad wheelbearings: First, raise the tire/wheel in question about an inch off the ground. Just to be safer, use an axle stand and rest the vehicle on the stand with the jack still in place taking some of the weight. Next, place one hand under the tire and the other on top. If you can move the tire toward you (if it moves around when you shake/move it) then the wheel bearing is undoubtedly shot. The wheel should turn freely and NOT move at all when you pull/push/shake the tire. Wheel bearings are generally associated with a loud, whine type noise that gets worse the more you drive.
If there is no noticeable noise, as jwko mentioned, the best thing you can do is to balance the tires and rotate them, back to front.
'00 Durango R/T 360ci 290hp (modded); 138,500m
'06 Pontiac G6 GT 3.5L 220hp; 44,000m
'12 Chrysler 200 Limited 3.6L 283hp; 13,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!