A strange noise can be one of the most elusive and deceptive of all vehicle dilemmas. With my 2003 1500 and 9000 miles, I just KNEW some pump or other device had gone bad. I had been ignoring the slight buzz in my passenger side dash, at 2000 rpm's, until my significant other, mentioned it. She's has NEVER said anything about ANY vehicle, I have ever owned. So, I had it checked-out. Dealer number one, couldn't discover the source, after keeping my auto all day, and requesting I leave it another day..."Nope". Next day, Chevy dealer number two, found the source within three hours. The transmission dipstick assembly, somehow was loose, and was rattling against the frame/firewall area.