Yeah, I get a clink from my chains every once in a while. I cannot seem to find it. I even jacked up the rear tires, had the wife in the cab and let the tires drive under power while I looked for it. Of course, I found nothing. No evidence of where they might be hitting, nothing.
(*I do not recommend jacking up your tractor and putting it to gear and looking around spinning tires with chains.)
That GPS looks awesome too! Great location!