What does a wheel bearing sound like as it goes out?

[Chigworthy]

I've never had one go out as I have usually replaced them when I do the brakes and have the rotors turned. After 160,000 miles of loyal service, my 99 Silverado is getting old. Anyway, I'm getting high-pitched squealing, very similar to the wear indicators in brake pads, but the sound doesn't occur quite like brake pad noise. I know that the brake pads can squeal even if you're not applying them, as the wheels tend to move around a bit, especially if not balanced perfectly. But it just feels different than bad brakes.

Anyway, would a worn wheel bearing sound like brake pad wear indicators? If I jack up the truck and spin the wheels, will I be able to tell if the bearing(s) are going bad?

Oh yeah: Independent front, 4X4, reg. cab long bed, disc brakes all around.

[feralBoy]

I sounds like it could be the wheel bearing. If you jack up the wheels and try to rock the wheel back and forth, if there is movement, it's almost definitely a wheel bearing.

[MrPink]

Is it real wet where you're at right now? It could just be moisture.