Some of the bolts on the side cover have a dowel type head near the hex. They go into certain holes on the side cover. These holes are a little bigger than the others. Your problem sounds like a broken shift fork. The bronze ones will break off where the engage the shift shaft on the cover. If it is broken and bronze, get the steel replacements for both 1-2 & 3-4. The steel ones were used like 70 and later. They had an extra tip on them that engaged some other levers in the later shift mechanism but you cut them off to work in the earlier covers. Old DC trick that was listed in the trans section.