51 B transmission issue

GBman

Member
A common issue wanting some fresh advice. Transmission can partially slide out of one gear and effectively be bound up as if it is in two gears at once. Wondering if there is a fix that doesn't involve a complete tear down of the transmission. I know one fork slides freely and the detent is stuck or worn out, I suspect this could be most of the issue. Can the rails and forks be pulled without pulling the clutch? I think the rails slide in from the flywheel side of the tractor, right? I'm thinking if I could replace or free up the detent this might solve the issue without total tear down. Thoughts and comments welcome.

Thank you all!
cvphoto144556.png
 
Did you try some penetrating oils on the pins and use a hammer and puch to tap on them? Might free them up.
 
Check the balls for being stuck & broken spring not putting pressure on the detents. The rails
have adjustment, watch it pictures looks to be adjusted correctly to me. Worn bearing or shafts
that need to be tightened up will let gears work apart & out of position. It is a lot of checking
some are hard to get to but kind of smiple to correct when you get there.
 
While not ideal you can get them out from just the Left side. There is a plate on the Right side that a flat spot on the shafts has to go back into. Also an adjustment for how far one of the gears can move is on that side too. If they seem fine you won't need to disturb them. I think the one I worked on had either a broken pawl spring or it was gunked and rusted up ? been a long time ago. But I did get them out and back in from only the Left side. Flywheel has to come off and so does the tin LH side cover.
 
Does the one rail have a bolt in the end to adjust the gear mess? The reduction cover would have to come off if it does. The G's do I know but haven't been in a B.
 
The bolt and lock nut on the Right side holds a plate which keeps the flats on the shafts in line. That bolt is really long and extends into the inside of the case to adjust a gear. Going from memory but I'm pretty sure this is correct. A quick look at the parts book will verify. I can't remember for sure if that adjustment bolt is to keep the reverse gear from traveling too far ?
 
in addition I think three rails have adjustment screws and lock bolts in the end of them , but they are on the left side.
 


Shouldn't have to mess with that plate on the right side of the rails. I remember reading through the book about that plate and it didn't really make much sense so I just left it alone when I went back together last year. All the rails are adjusted on the left side. I don't think there's an adjustment for the 4th and 6th rail.

If you do take it apart I suggest looking at how much the palws walk back and forth inside the cast iron gate/fork. On the 1st 3rd and reverse one I drilled out the bore and put a bushing in it so the pawl couldn't walk back and forth while detented in gear. I also highly recommend welding up the rails where the pawls ride on the rail. Then grinding them smooth again
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top