Hi All,
I had exactly the same problem with my Plus 8 since she was new in 2003. The dealer (a good one) told me that it was a "normal Morgan noise". I checked everything but I didn't find anything wrong. I even made a claim to MMC, but I didn't get any good answer ("they all do that Sir..", very well-known answer). So after a lot of searches an American Morgan dealer told me that it was a known trouble probably because there was a little too much play between the splines of the hub and the ones of the wheel, but it is possible to go to 200lb/ft. of torque to tighten the wheels (16" stainless steel spokes wheels). So I packed carefully with copper paste and tighten to more than 200lb/ft. and it worked. The noise regularly comes back every year, when it is time to remove the wheels to repack the splines with fresh cooper grease. It works now for 9 years so I think my dealer was right, and after a lot of Morgan meetings, I realized that I often hear the same noise at rear end of many Morgan.
I hope it can help.
BR.
Daniel.