Tractor Repair: David Brown 1210, pto drive shaft, pto shaft

Question
Could you help me i need to know a likely cause of my David Brown 1210 2wd sticking in Reverse Gear. it was reversed into position and stopped. when restarted it would not move only in the reverse direction. Also I have taken the tractor apart but have got stuck do i need to remove the long PTO shaft prior to removing the Gearbox?

Answer
Hello,

  Usually the problem is just that the bottom of the shift lever jumps out of position where it engages with the shift rails.  In that case, you just unbolt the shift lever housing and reach down into the transmission with a long screwdriver or something and pry the shift rail back to neutral, then reinstall the shift lever and you're good to go.  But occasionally, a shift fork or rail breaks, or a roll pin in a rail shears off, or a bearing fails and the gearbox has to be taken apart to fix it.  I don't know how much you have apart already,  but yes the pto drive shaft has to be removed before the gearbox can be removed.  The pto MUST be in gear before splitting the tractor or removing the pto shaft, otherwise the drive coupling inside the pto housing can fall down inside, requiring you to remove the pto housing from the back of the tractor to put the coupling back in place.  I guarantee you will only make that mistake once and you will never forget it.  With the transmission top cover removed, you should be able to see a broken shift fork or rail, but to remove the gearbox will require splitting the tractor and removing the rear axles because the gearbox and differential are one unit.  The differential bearing caps could be unbolted to separate them, but then the bearing adjustment will get messed up, SO DO NOT DO THAT!!  The gearbox and differential should always be removed as one unit, and then it can be stood up vertically making disassembly much easier.  A few times I was able to cheat and fix something by splitting the tractor and removing  the front part of the gearbox without removing the whole gearbox from the tractor, but there are only certain things that can be fixed that way.  It would depend on what the actual problem is, which obviously I don't know without seeing it.  One more important thing.  If the gearbox does have to be removed, engage the diff lock and tie the diff lock pedal down with some wire before removing the rear axles.  Otherwise the internal diff lock coupling and spring will fall out of place, making it extremely difficult to get them back in when assembling it again.

                     Good luck,

                           Arnie