Mystery Noise??
 

I have an F-350 CC, Manual, 4x4 SRW PSD 7.3. I have a noise I cannot figure out.

I recently removed the rear brake drums to check the brake shoes. When I replaced them, I now have a noise that appears to be comming from the left rear drum.

The noise is not directly related to speed or rpm's. It is not related to rough or smooth pavement. It sounds like something lightly hitting the brake drum in almost a random pattern. It does not get faster when speed is increase. It goes away below 5 mph usually...I have looked over the entire brake setup 4 times. Cannot find anything that appears to be rubbing or has any indication of contacting anything.

Is there anyother moving part that would emit a sound that would be similar?

It is driving me nuts looking for it.

The brake shoes were 60-70%, wish I had not taken the drum off now..

Any ideas....