Good news, the dealer was able to locate the noise after some crafty troubleshooting and it was as simple as a dry rubber trunk seal. They put some grease on it and the noise is gone. I would have preferred they just replaced the seal, but the noise is gone & I have a record if it ever comes back. Apparently it took some time & effort to find the cause, so my impression of dealer service is better now then it was in the past.
