Not going to believe this one.

[roscoe]

Update. A while back I made a post about a strange intermittant drive train lock-up I was having with my 100. I won't bore you with the details. Finally it got frequent enough so I could actually do a little trouble shooting. It seemed that when it happened the shift pattern felt abnormal and I couldn't get it into any gear until, after a bunch of wiggling of the shift lever, all of a sudden the problem was cleared and off I'd go. I finally said to my wife, damned if it doesn't feel like the little swivel on the bottom end of the shift lever is somehow popping out of the cup in the selector fork. But that could never happen... could it? Yup. I had two gaskets on the stack up of parts that hold the shift lever into the gearbox, both rubber,one very think and one fairly thin. It turns out that the thick gasket was raising the shift lever retainer up too high. The bronze swivel WAS actually coming out of the cup on the selector fork and by wiggling it around it would eventually find its way back in place and off I' go. I was lucky that it didn't fall off the end of the lever. I used a thinner gasket, torqued it up and it hasn't happened since. I can not begin to tell you which gear was not lining up so as to cause the gearbox to lock-up, but it must have been ugly. For some reason unknown to me this never happened at speed. I think it took going into reverse or going from 3rd to neutral while coming to a stop(we all wiggle the lever to be sure we're in neutral)for it to happen. I won't be pulling my gearbox this winter. Yessss...

 

[dvu101]

Jon
I think this is the same problem I have been having with my BT7 centershift. If I shift slowly but firmly into gear I do not have a problem. If I shift fast or do not pay attention to a detailed shift then if seems the shifter lever somehow pops out of gear and does not go into any gear. I have to fish around to find the gear, pull the shifter up and pop it in and off I go for weeks to months. Could this be the same problem? How did you fix it.

 

[roscoe]

Scott,
If you have a Moss Catalog or shop manual that shows the breakdown of the center shift gearbox, you will see that under the boot is a large circlip that holds a washer and a large spring in place. The spring (which I do not have on the side shift GB) is held in place such that it pushes down on the ball that fits into the casting of the shift bore. Extending down from the ball is the shift lever extension that has the little swivel bush that fits into the cup on the control shaft. If your spring is broken or missing, or if the circlip is not doing it's job you would not have proper downward pressure to keep the bushing in the cup and perhaps it could pop out. Or the swivel bush could be heavily worn. Never having had a centershift GB it looks to me as though you can actually see underneath where the control shaft exits the top cover to see the engagement of what I'm talking about. Once you see the shop diagram you will see it is pretty easy to take this apart. Perhaps others with more direct experience on the center shifter will chime in.