Hey Bill and the others at Sailnet who responded:
thanks for all your thoughts. I have never taken apart a Yanmar 3GM transmission or shaft components so I am not sure if I explained the set up accurately. But it does seem that many more esperienced sailors are also puzzled by the circumstances. I have not had an opportunity to investigate further because I had to abandon my trip and return home. When the shaft is pulled this coming week I will report back with more details so that we all might get some insight as to what went wrong.