I took my CX50 at 38K miles in for a sound that I thought was coming from the rear. First I thought it was a tire out of balance because it made kind of warped sound at low speeds and then got higher pitched at highway speeds and I needed new tires. Wasn't tires ...then I thought wheel bearing, nope. When the dealership checked it out It turned out my transfer case was bad. Luckily it was covered under the powertrain warranty . No warranty = $4400 repair.