in the past when i had 4 speeds and i had problems with second gear i found the brass synchro split. the early (70 and earlier?) synchros were machined differently from later synchros. the later synchros were different and were stronger and didnt break near as often as early style synchros. seems i remember you change the synchro and its holder as an assembly. brewer probably sells a kit to do this conversion. the steel slider teeth and the gear teeth look preety good in the pictures, not a lot of wear for a gear box that always got beat on back in the day.