Mine was replaced after the rear fell apart. First noise appeared to be a whining sound after I heard a giggling sound. Took it to the Ford Truck Center and they couldn't find anything wrong. On my way home it started falling apart, gears breaking teeth, and the rear basically bucking up and down. Thank God I was able to get over to a turn lane and off the main road. Spoke with a Ford Rep later that year and asked whether they had any problems and his reply was the rear, provided by Dana, had a few few issues from one plant. The bolts were not torqued properly, resulting in them coming loose. The is what happened in my case. Once fixed, it has been quieter than it was on the day we brought it home.
2007 Georgetown 370TS
aka - RAYNMKR