loud high pitch hum/whine coming from under the hood
Yep. that would be the one. 
Grab your tensioner pulley with a wrench, (like you were going to take off the belt), and with the engine running, CAREFULLY apply a bit more pressure in the tension direction. (tighten the belt.) Noise get worse? or better?
Be VERY careful here, no loose clothing where the belt can get ahold of it. You really wouldn't care for that event........

Grab your tensioner pulley with a wrench, (like you were going to take off the belt), and with the engine running, CAREFULLY apply a bit more pressure in the tension direction. (tighten the belt.) Noise get worse? or better?
Be VERY careful here, no loose clothing where the belt can get ahold of it. You really wouldn't care for that event........
Junkyard or you can go to the dealership.
Still have not found out where the noise is coming from. The power steering pump fluid level is normal, but I did a while back, change the steering gear box, and the power steering pump was always hissy ever since but never whined high pitch like this noise is. It sounds like its coming from bewtween the alternator and the a/c....the intake manifold is where it sounds like the noise is.
I had the same problem with my 99 it went away on its own. It too was coming from one of the pulleys. I have another problem similar to yours but my is a ticking that increased as the rpms increase. Its coming from under the drivers side valve cover. Any ideas what it is or what I can do?
i may sound stupid when i say this, but it's most likely your catylic converter.. i had this same problem with my 99 dodge.. at the top of 2nd and 3rd gears i would hear it come on for a second or two.. i guess it couldve been a crack in it or it was just clogged.. but i'm pretty sure this is what's wrong with it.. i replaced mine with a magnaflow hiflow cat and it sounded better, improved power, AND got rid of the noise.. so all in all its a win win situation!
temporarily remove the belt and operate the engine. does the noise stay or go away? be careful- only run the engine for a minute or so. - no belt means no water pump, so the engine will quickly overheat.
power steering pumps can make a lot of whine,
power steering pumps can make a lot of whine,
Still havnt been able to find where the noise is coming from, but its definatly still there and rather annoying. Would the a/c make that noise with air off? Its been really cold here so I havnt been able to really look that deep into it, but I have tommorow off and will see if maybe I can find something. It only makes the noise when the engines warm after driving atleast 15 miles. And its a whine/hum that gets loude then quiet, then gets louder then gets quiet..within like 1 second surations. I will see if I can get a video on here soon and maybe you guys might know. But I can hear It in the cab up by the dash.







