I changed my belt tensioner and serpentine belt. The new got shredded on the inside. I noticed the harmonic balancer vibrates at idle however it smooth out when you give the car gas. Is this normal operation for a 5.3L LS4? I have replaced the belt and so far no problems but the harmonic balancer stills operates the same. Any suggestions?

 

There really shouldn't be much of a vibration from the balancer. if you can see it wiggling the rubber elastic ring probably is getting bad. Might be a good idea to have a shop or someone else take a second look at it. Good luck