Belt sqeeling..or is it?

I think the lube wear indicator in the gas gauge.

 

Bad idler pulley on a 3406 caused me the same grief. Three complete sets of belts, and prolly a gallon of belt dressing later, I gave up, and went to local mechanic shop, as I was walking in, the wrench poked his head out from under a truck and asked if it was me who just pulled up with a bad idler.

No substitute for experience sometimes.

 

Try spraying penetraiting oil on each of the pulleys. My ISX had a bad pulley, not the tensioner one. It was usually at start up and then would quickly go away, for about a year, then suddenly got worse and continous.

 

What was the resolution to this. My truck is a Vnl with Cummins just started doing this belt squeal. Tensioner is new belt is new and still doing it.