Just yesterday on my way home from work i started hearing a loud rattle it sounds like metal on metal almost like a snapped rod but i still have compresion in all cylinders. i took of the alternator and belt and was playin around with everything and i think it might be the harmonic balancer. with everything back together i was spinning the motor by hand and i noticed the large bolt in the middle of the balancer wasnt spinning so i kept turning the motor and then i heard the sound and it seemed like it was catching and then the bolt would spin ...i hope you understand what im saying. if theres anything you guys can tell me to help i would really appreciate the help

Do you see cracking in the rubber on the balancer?

Well, if you were turning the motor by hand and the bolt in the middle of the balancer wasn't turning, you must have been turning it via one of the other accessories, or the belt?

It does sound like your balancer is crapped out. The rubber inside it cracks and falls out, as mr. Boost is getting at, and it creates major slop, and a noise kinda like you describe.

Not too fun to replace, but better than a rod, for sure!

yeah i can see the rubber all the way around the outside pully is dry rotted and cracked up. i ordered the balancer ... it was $245 but i got it for $154 cause i work at a GM dealership ha ha

Aftermarket ones are only about $95 US. You should shop around.