Shudder/Vibration in Drive train.
 

Recently my 2000 Explorer XLT (4.0L 6-cylinder) with 270K miles developed a "shudder" that vibrated the steering wheel and the whole vehicle. It first started when passing a car at 75 mph, but then started at lower speeds. It seems to go through a speed range (e.g., 45-55 mph) and clears. I took it to the "expert" in this town who everyone swears by. He was a lead mechanic at a dealership for 20 years then went out on his own. (I only say this to establish his credibility). He announced emphatically: it's your U-joint. So he replaced the U-joint and NOTHING changed. To preclude from being nickel-and-dimed by this guy, can anyone offer some suggestions (for the car problem,. that is...)

Most of the time, when the steering is affected/involved, it usually is originating at the front of the vehicle. It could be a tire, suspension component, steering component, wheel bearing , wheel balance, differential and maybe he replaced the wrong u-joint!