I recently tried to sort out the problem, once and for all. The whole thing seemed loose and a bit sloppy and the reverse interlock did not seem to work. I took the whole assembly apart on the bench and found that the grooves where the pivot pins fit into the pivot ball were pretty badly worn. I welded it up and ground it down so that everything fits a bit tighter. I also found that the reverse latch interlock was hanging up on the bottom of the shifter rod. When I checked the parts manual, it was not together correctly. This told me that it had been apart and messed with in the past. More on that in a minute.

I sorted that all out and put the whole thing back together again, and it promptly jammed in second gear again. When I took it apart again, I noticed that the first and second gear rail was pushed forward (into second gear) when the end of the shifter rod was still in the neutral position . I have heard of gear shifters jumping out of gear, but in my case, it seemed to be jumping into gear. I could not figure out how the rail could be moved without the shifter moving it.