I just purchased the GX460 from a family friend. The car has 48,000 miles and is in good shape. The other day it started a very low whine at startup and will continue until about 15 seconds after I kill the engine. It is not the audio or A/C, as when I turn both of those off it continues. I even thought it might be related to the Bluetooth, so I disconnected my phone. No luck. When I took it to the dealer after driving it for over an hour, it wasn't making the sound anymore and wouldn't when I shut if off and then back on. However, when out of the car for 10-25 minutes, it starts again. Any thoughts?