I am debugging an issue on my 03 FLHTCI and took this video today. Could this be what you are describing. I also held my finger on the drive gear(belt) and felt it moving as well. My gut tells me it is the main shaft bearing. I will continue with my challenge in another thread. I don't have enough posts yet so I can't post the link. If you enter "video of wobble in a 2003 flhtci" in the search bar on youtube you should see it. It's only 9 secs long. Hope this helps.