Ok so i am having this annoying squeal coming from under the hood. I have had no luck figuring out what it could be.
On start-up it will chirp a little bit, but once i am driving down the road it get louder with RPMs, but when the truck shifts into overdrive it either goes away or is almost non-existant. I have replaced the belt, idler pulley and the tensioner.
From what I can see there is not any leaks coming from underneath or anything like that. The sounds does seem to come from either the power steering pulley, or the water pump. Not sure which one to try next,
I have also tried to put a steel tool to everything to see if i could hear anything, and still couldnt figure anything. If you have any suggestions please let me know. I am lost. Thanks.

 

Do any of the pulleys wiggle with the belt off? Thats how I diagnosed my water pump. It also was making a slight squeaking sound when I'd spin it by hand.

 

Find out if it is a chirp or squeal:
http://www.youtube.com/watch?v=cW_wpE3hG5k

Solutions to Chirp:
http://www.youtube.com/watch?v=X9qMtVVLXeY

Solutions to Squeal:
http://www.youtube.com/watch?v=sli3FnPfdQ4