Not to hijack, but be sure to let us know what it is. My truck periodically (like once every couple months) makes a god awful high pitched wailing/rubbing noise just like you described.
I find if I bring the truck to a stop and hit the brake pedal, it goes away after about 5-10 seconds and stops completely until the next time.
It sounds like its coming more from the bell housing/tranny though.
Is there anything turning when the truck is sitting still idling that the brakes would affect when pressed?
