power steering whine???

I have a 02 Z71. When it gets warm there is like a whining noise only when I turn left. It kind of sounds like a powersteering pump when its out of fluid but it sounds more in the steering column. Anyone experienced this?
Thanks

probably the pump

I have a 99 GMC and have the same thing, I think it is more of a squeak in the colum as the engine speed does not effect the noise.