Ok, over the course of the last month, I have replaced the idler pulley, the tensioner pulley, the alternator (needed), and last week the belt. I had the truck in the shop today to get the alt replaced under warranty. the mechanic wanted to replace the belt, because he said it was jumping around. The belt I bought is a Dayco belt. From what I can tell by its tracking pattern, it has a 1/8 inch band at the front that is wearing more than the rest of the belt topside.

the only thing I can tell that could be the culprit is the tensioner itself. It seems to be at an angle with the pulley angle towards the front of the truck a bit. Also, the belt wants to run near the face of the pulley. Is it possible that the tensioner needs replacing?

Thanks

 

I would take a long level/square and check all the faces of the pulleys to see if they are all in the same plane. If one offset then that is most likely your problem.

As for the tensioner pulley......are you saying that it is not perfectly parallel with the belt system?

 

Yes, as compared to the other pulleys, it appears to be angled slightly more forward than the others; although, it still has good tension on the belt itself. Barely moves when blipping the gas.

 

I would say that is the problem, or at least the first point of attack. Have you checked to make sure both bolts are tight (pulley and the assembly body)? If they are I would say replace the assembly.

 

I read a thread on a forum , don't remember what one , that someone put a shim washer on the locator stud on the behind the belt tensioner . Not the pulley , the tensioner itself. That corrected the angle of the pulley so the belt ran true .

 

That sounds like a good idea. I'll have to do that once I have some free time. Thanks!

 

Did the old belt run off center or just "jumping around"?

 

It is hard to say what the old belt was doing. It did not seem all that old to begin with. I was just going through replacing items to eliminate any noise from engine bay.