My RAV is very well maintained, needs nothing to be done except the next maintenance on schedule after the 90,000 mi. point. Brakes, tires, exhaust and all items are up to date.Toyota oil change and fluid refills are also recent, done every 5,000. mil per the manual, including tire rotation EACH time since I bought it. In Early January 2011 I began to experience a vibration from under the vehicle. The first thought was that it was an exhaust rattle and had it checked for looseness. All ok, nothing was needed, the vibration remains and has grown worse. It occurs between 35-45 mph, and ceases if I let off the gas - but to maintain the speed in that range it is LOUD enough that anyone in/out of the car can hear it. Add to that now, an occassional sound as though I am on a rumble strip - exactly at 40mph. I went back to my mechanic because I was concerned about safety. He kept the car for the day, drove it, put it up on the lift and checked everything below and wheel assemblies & brakes. I am mechanically safe and sound., but now I'm at a point I can't stand this anymore, and actually if I were to consider trading it in, this problem can count against the integrity of this vehicle. Suggestions Badly needed!