happens to me too, only when it is very cold the night before. The last time it did it i used the wooden dowel trick....while the truck is making the bearing squeal noise, touch a wooden dowel to the base of each pulley...ie alternator, tensioner, ac unit, etc. and put your ear on the end of the dowel...you will notice a distinct different noise when you touch the right one.

anyway, i did this the other day and i think i pinpointed it to the a/c unit making the noise. so i am gonna try to force the dealer to change the a/c bearing/clutch assembly under warrantee. i might take a quick video on my cell phone to prove to the dealer that it is making the noise. i'll let you know how i do. and if anyone else finds that it is the a/c unit bearing let me know....thanks