WOW, that was fast. I'll give that a try on the way home and let you know what I find. Thanks for your help.Quad T said:I found if I adjusted the mirrors to point inward just a bit more the whistle went away. When I pulled mine out for towing my fingers were on the glass and I angled the mirror out more and the whistle started. Once I angled the mirrors in a bit more so the gap between the edge of the glass got closer to the inside of the plastic housing the whistle went away.