Originally Posted by Seattle S65B40
Yet another alternative source to the sound. Interesting. Diagnosis of this problem could be harder with so many different possible causes. The same can be said for recreation of the problem for service techs. Luckily when I took mine in the second time, it was continuos, and the tech knew right away what was up (in my case, pebble INSIDE RR rotor - not between rotor and heat shield).
My Cowbell/ping issue was pretty easy to repeat for the techs to listen to and diagnose.
I just thought I'd throw it out there because I came across this thread while searching for any info on my problem.