ok, so my buddy's 6.2 is breaking alternator belts like there's no tomorrow. i think he's gone through about 6-8 in the last month and a half. the pulleys look like they're lined up well, but something is clearly not right. the belt pulls pretty straight across the top of the alternator and water pump, as well as up the crank and over the water pump, but as it goes around the alternator and back down to the crank, it wobbles and shakes like the belt is crazy loose. i know it's tight tho - i've tightened it myself a few times. he bought a brand new belt today and broke it on the 2 mile trip home. the only thing i can figure is that perhaps the thrust bearing is allowing too much play - crank moving back and forth in the engine, or the crank pulley is damaged in someway (it's off of a different 6.2 and his alternator is new, so that shouldn't be bad). any thoughts?