So I completely missed that this is an electric assist bike! I thought PAS was an incorrect naming of IPS. Why wouldn't the electric hub not be a person of interest?! I would LOVE to be wrong, but I doubt very much that the rear hub is the problem. Unless there are ceramic ball bearings in that hub I can't think of any reason a hub would make a sound like that. OTOH I can think of a half dozen reasons easily why an electric hub might make a sound like that. I am (again) assuming that by the bike was tested with the PAS on and off that that did not mean that the hub was removed entirely and a different wheel tested in it's place. My LBS is frustrating in their unwillingness to even sell parts for a recumbent or e-assist or anything not a standard roadbike. But this LBS should have long since recommended the o.p. take the bike to a dealer of e-bikes because I am betting the farm that the problem lies somewhere in the motor. This really isn't fair though, as much as I (we) like a challenge, the people who have SEEN this bike, up close and personal, are in the best position to troubleshoot. All the rest of us can do is speculate wildly.