I do ??? The one i took off is exactly thw same as the one i put on and that one was original from late 01
that looks right. on my 02, it would do the exact same thing you speak of. the difference between the 2 has to do with the rib spacing. does it feel like the belt fits in there like the pulley on the alternator?
Dunno if it'd work in neutral, but have someone rev it to 3k and let it go to idle, see how much movment the tensioner has.
you have 2 different options for tentioners on your truck. you have the wrong one. i will try to find pics...
Maybe a bearing is going out on one of your pulleys. And its dragging under load. Causing the belt to get chewed.
Have you also checked the route of the belt? To make sure it won't rub on anything. Checked that there are no burs on any of the pulleys? Or there are no burs from the engine or accessories bracket hitting the belt?
Mine did this. I replaced the tensioner and both idlers and haven't had any more problems.
I learned that the hard way!