I have the strangest problem when backing up a steep driveway, which is perpendicular to the street. Ordinarily, I pull up to the curb just past the driveway, put the car in reverse, and then crank the steering wheel all the way to the right and begin backing up. At the point when the back end of my car (1994 E420) is on the driveway while the front end is still in the street, about the point where the front end is close to bottoming out on the street, the car makes a loud grinding sound, as if a fan of some sort is hitting something. I also noticed that if I straighten the steering wheel out at the point that it is making the noise, the noise does NOT go away. So it seems as though the noise only occurs when the front end of the car is very low to the ground.

My mechanic has been unable to duplicate this problem thus far, and I am hoping to get some suggestions from the forum as to what it might be. I'll be taking the car back first thing Monday morning, so if you have any ideas, please let me know. Many thanks in advance.