Fan Blade rubbing Crank Pulley!!

This Jeep of mine has turned into a HEEP

Driving home lastnight i noticed it started to squeal a little and i didnt worry because i had a new belt ready to put on it anyways. but right after i filled up i started it up and it was screeching like crazy! So i drive off in a hurry and get home. Go to start it up this morning and the belt flys off....looked under the hood and it came off of the fan pulley. And every one of the fan blades is hitting the crank as it comes around.....everythings tight..the pulley doesnt wiggle in the least bit and everything looks in order from what my eyes can see. Anyone ever had this happen?

if you could post a pic of the front of the Harmonic Balancer (crank pulley) it would help. it sounds like it is coming apart and the outer section is moving forward. this would cause the belt to be misaligned and come off, as well as the fan blades hitting the pulley. another possibility is the fan clutch has gone bad allowing the fan to move back and forth, but most likely its the balancer.

x2. thats what mine started to do when the harmonic balancer went bad.

Yep it was the balancer....sucker nearly came all the way off on its own!!!
I was actually able to pull the outer part right off of the inner piece while it was in the jeep