Can the harmonic balance come loose?

This engine has about 10, 000mi on a rebuild.
I was driving it today and I was hearing a noise That sounded like something was loose. I only would hear it when I would stop. When i would speed up the sound would go away.
I didn't check real hard yet because I'm not feeling real well today but when I looked it appeared that the harmonic balancer may be loose and that is what is making the noise. Do you think this could less to other troubles like the crank shaft, or bearings?
Thanks.

Oh this is on a 360.