Has anyone replaced just the idler pulley versus the whole assembly. I don't want to spend a pile of dough for just the bearings and pulley.

 

I replaced the whole tensioner. I think it was 120 at oreilleys or napa.

FWIW, it was an extremely easy job!

 

I haven't done it yet, but you can get just a heavy duty idler pulley for the truck:
http://www.psdieselproducts.bizland.com/index.html
Don't know how the price compares to the whole assembly, but thought I would let you know of that option.
Mishkaya

 

Usually the tensioner wears out at the pivot point and starts letting the belt walk into the alternator before the idler bearings go. If the bearings on the idler wheel are bad, replace the whole tensioner. It would suck to spend money on the new idler and then have to buy the whole assembly later.

Advance Auto Parts shows a Dayco unit for $86.

 

I can attest to that. I replaced just the idler pulley a year or two ago and recently I noticed the belt looks like it is starting to walk off the idler pulley. So now i'm going to have to replace the whole thing. Its OK though the idler pulley was only 10 or 15 bucks.

 

Make sure you get the metal wheel pulley.