Hi Mike:  When my SM, a 2001 #335, was about 4 years old the main sail furling gearbox motor shaft sheared for unknown reasons.  Ray Eaton, Joel's Ft. Lauderdale guru at the time, (about 2005) said he had not seen that happen before. I have not had this happen again despite the boat being now about 18 years old (but then I have only sailed her about 18,000 sea miles during that time). About two years ago I ordered a complete assembly (gearbox, motor, mounting ring and cover) from Maud as I realized that even though I had several spare gearboxes I didn't have a spare motor.  That entire assembly was available from Amel at that time. 

Good luck in securing replacements or alternatives. 

Sincerely, 

Gary S. Silver
s/v Liahona
Amel SM 2000 #335
Puerto Del Rey Marina, Fajardo Puerto Rico