The stopping pin on the B-axle bracket that contacts the derailleur hanger broke. I just paid good money for a partial XT group last yr and the $120 something rear derailleur is broken and I didn't smash it against a rock, log, or stump . So far, I don't see a part # for it, but it makes no since to me that a part that comes off does not have a replacement part #. Has this broke on anyone else? Does anyone think or on if I could get the bracket from Shimano or is there someone out there that has one for parts?