I experienced a rather interesting and easily solved problem. My RTL-E developed a screeching sound that was very similar to the noise a bearing makes as it fails. The noise was related to the rotation of my wheels and varied from incredibly loud at very low speeds to very faint at high speeds. I drove by the dealer's and they had it fixed in a few minutes. A stone had become lodged between a front brake rotor and the heat shield. They were able to dislodge it by removing the wheel and pushing on the heat shield, but advised me in other cases they have had to remove the brake caliper and rotor to solve the problem. To get to and from my home I drive down a 1 mile gravel road. I hope this was a once-every-10 to 20 year-occurrence. If not it could get to be a RPITA.