WOW wish some one would post on this topic as I am having the same issue...

 

What year is your truck? If it increases with more rpm, I'm thinking Turbo.

 

1) turbo turbine damaged, or bad bearing 2) Alternator bearing 3) powersteering/hydro boost pump is dying! Mines weak....wines sitting still, slow turning, or on the brakes hard at a light ....check it all out...spray ur alt down with some silicone spray, see if the sound changes...just my .02

 

It was a bad idle pulley. Replaced it and now it's good to go.

 

Having the same problem,how much it cost you to replace it > and where is located,thanks

 

Sorry to hijack your thread but Im having the issue with my 00 7.3L... spent 280.00 replacing the p/s pump...I posted earlier then I saw its in the 6.0 forum... I'm hoping nothing super serious... is there any way to see if its a pulley or the Turbo? As it seems to be rpm related, and when I replaced the p.s. pump one part of the dual pitch noise went away... it sounds like a supercharger whine is the best way to describe it...
Any ideas

 

Yep that's what mine sounded like. I would check your idle pulleys.:nod:

 

I also have a whining noise, It's coming from my wife:doh:. what will it cost for replacement:hehe:

 

my did it for 2 years then idler pulley let go at 1 o clock when you look from the front $ 35 pulley and $54 for the belt + 200$ for the tow