Harmonic balancer

[Paulsdodge]

I was checking my owners manual for my truck yesterday and it calls for you to check the vibration balancer at 12000 miles. What do I check ? Is it the bolt tightness, or do i check to see if the rubber between the mating metal surfaces appears to be intact, or both?

 

[DPKetchum]

There probably wanting a visual inspection of the rubber.