The engagement part of the Syncro assembly is held in with an internal snap ring
on each end. It sounds like the 3rd gear end has disengaged and is locking up and causing
the problem you described. If so it will require a tear down to determine the damage caused.
It likely will need that component replaced or rebuilt.
Fred
Thanks for the explanation. I can see the front and rear snap rings so at least they are not chewed up somewhere. The repair manual does say a poorly fitted ring will not permit proper syncronizing of gears during shifting. Out of curiosity, what is the energizing spring for?
