I just started hearing a loud high pitched whirling noise coming from the right rear wheel area.
The truck is an 02 PSD Crew Cab 4x4 with 6 spd.
The noise only occurs when cold and disappears after a few miles of driving.
It sounds like an ungreased bent wagon wheel, if you can imagine that.
It is not the rotor, as the noise continues even when braking hard .
It only stops when the wheel stops and after the truck is driven 3-4 miles.
I'm baffled

 

are you sure its the rear, super dutys have had problems with the front axle dust sheilds and vaccum hub seals making a squealing noise. the noise usually shows up when in 4x4 but can also be present in 2x4. hope this helps