Hello,
On my 1991 Sonoma when I drive between 5-20mph I get a high pitch whining noise. It is loud because it turns heads in parking lots. Well I got the truck up to 40mph on a straight road late at night, and turned the truck off and put the tranny in neutral. It still made the same noise. What can this be, I took it to a few mechanics, but they can't find anything wrong with it, because when the truck warms up it usually quiets down.