Noise coming from underneath the right front of the car

[zero4588]

I have some kind of girnding noise coming from the right front of my car, which is a 98 E320. It is most obvious when I am accelerating at low speed, say 5 mph, or decelerating to low speed, say 20 or 35 mph. Yet, the grinding sound slowly went away at high speed travel, say after 60 mph. I also had the dealers check underneath the car for a number of times. They checked bushings and related suspension components and could not accurately pinpoint where the noise is coming from. Actually this problem has been with my car ever since we bought the car new, and the dealers didn't seem to be able to diagnose what the problem is. Could this noise caused by car's alignment? Because I've already had several alignments done by different dealers and shops during the past few years, and none solved the problem. So I would really appreciate it if you can give me some inputs on this noise issue. What's your take?