Lately my truck has been making a loud noise white it is revved up warming itself. I have yet to find where it is originating from and it's very annoying. I take off from my house truck not warm yet and 1st gear, good 2nd gear, good, 3rd gear squeaks like a crazy at low rpms sounds like metal on metal. The trucks motor and turbo don't have 10000 miles on it yet. It was recently rebuilt bulletproofed and turbo replaced. I don't know what to look for or where the sound is coming from it's so deafening. I have to stop it from revving for it to stop. It doesn't do it at 1700 rpm+ only at low 1500 or below. Turbo makes boost perfectly with the tune I have 35 pounds under hard acceleration and no defects. One of the turbo boots have black soot on it but it's coming off of the intercooler. People are says turbo bearings but I strongly disagree because of its age and its performance making boost with ease. Low acceleration it is loud, moderate acceleration it's barely noticeable and rarely does it. I need any help I can get, it's very irritating in the mornings having to babysit the truck so it doesn't wake everyone up in a 5 mile radius because of this shrieking sound

 

I would bet it is a belt or idler fully. That or a mouse with a megaphone... Probably a belt or an idler pulley as very few mice have megaphones.