06 4 wd sport making loud noise

Every time I start my truck I have this loud noise in the engine bay. Can't pin point the problem. Was thinking I had a vavumme leak but found nothing. Replace both donut gaskets post cat.
Friend suggest nay be a pulley going out. He told me to spray some WD40 I'm there one by one and start it and see which pulley it was but I havnt tried just yet.
Any suggestions?
I cant really describe it. Just sounds like a loud vacuum leak or something. Sort of like when you breathehot air into your hands. But louder.

 

Probably a pulley, pull the belt and turn them each by hand to see if they feel funny or make any noise.

 

I'll try that. Should it just sound smooth or ?

 

It should feel smooth, if it feels notchy or is binding then its bad.

 

Now if it's been doing it for awhile. Is it possible that I messed something else up or is it just the noise that's annoying. I figured maybe some dirt got in there

 

So removed my belt. I see one belt tensionsor and like 3 other pullys that I guess keep the belt in place.(gold)
Some felt smoothie and the others just sounded like the bearings where a little dry.
Sprayed some white silicone grease inside them. And cleaned up the excess.
Still has the sound.


Honestly sounds like an exhaust peak or something but I'm not sure.