The overdrive transmission is by Borg Warner, search that and R10 and/or R11 terms for plenty of articles. It is a 3 speed front trans with a planetary gear set behind that. It provides a 0.72 reduction when engaged.
'59 Apache ‘21 Beta 390RS ‘18 BMW R1200RT '12 Ford Flex '13 Aprilia Tuono ‘11 Ducati Hypermotard Salisbury, MD
