I have this whining, more like droning. Sounds very similar to having low power steering fluid, but not because the level was right in the middle of normal and I put in a little bit just to see if that would change anything, and it didn't.
The sound will start when the RPMs are lower than roughly 3000 RPM and will start both in gear and out of gear. Out of gear, revving the engine gets rid of the noise maybe 50% of the tim, in gear giving a little gas is garraunteed to get rid of it. It has never gone away by itself and it will not consistently do it right after start up or while idling, or when in gear. It doesn't seem to have a specific state that triggers it.
I popped the hood and I am having GREAT difficulty finding the origination of the noise as well. Seems to, at least, not be coming from anything too close to the hood, rather something deeper in the bay, but I can't be sure of that.
Any help would be GREATLY appreciated, it's driving me nuts,
Chris