any solution found to this mysterious squeaking? I just did a tune up and had to replace the tensioner assembly and belt and now have a similar problem.

 

try silicon grease on the belt, and all the pulleys, spray each individually, if one stops squeaking when you spray it there is your problem!

 

I had my truck in the shop today for a tranny issue, and they said the pullys had gunk on them, so they cleaned them up and the squeak went away.

I haven't picked up the truck yet, but the hopefully that was the issue.