Sometimes my belt squeels, and I have no idea why. It only does it under load, not idling. Really though this is a fairly intermittent problem, amplified when the belt gets at all wet (my hood has one small leak). Also it consistently skips one rib towards the rear of the car if I go above 3k rpm. Are these problems correlated? Maybe when I shift at a higher rpm the change from lots of torque to none is too much for my old tensioner and it skips a rib? What about the squeeling? Thanks~

 

What belt brand are you using????? Seems like the tensioner is worn....

Plus check the idler pulley...

 

Sounds like the tensioner is weak if the belt is shifting around. The belt has probably been abused by this so I recommend you replace the belt too.