So I've had this annoying mechanical whine that almost mimics a teapot whistle that occurs on deceleration while off the throttle. it's relative to the speed of the wheels, not to the gear or what have you. I took it in to the dealership this last weekend, after having brought it it last summer for the same reason. this time, they put it on a lift and had a mechanic rev the engine up and let the vehicle decelerate naturally. This produced a very clear and distinct whine once isolated in a shop. After sampling the oil, finding it to be black and metallic, the verdict is that a bearing or something had let go within the transmission, and a new one (under warranty) was placed on order.