GXS

Hey everyone. I have a problem. Our RX is an old one, purchased when they just came out, so maybe that could be a factor. When stepping on the pedal at low speeds, the car is shifting from 3 to 4, our RX makes some kind of rattling noise. It seems it's coming from under the car. Has anyone had this problem? And there are no Lexus dealers in our area. I'm also getting another strut mount replaced. Thanks.