The transmission gear selection lever randomly pops out of first into neutral. Seems to happen randomly, pushing material or just driving. It's pretty infrequent, not a constant thing. Maybe once every other hour of operation. Is there an adjustment somewhere to deal with this? Someone mentioned something about a transmission interlock related to the clutch lever. I don't know if it does it in other gears, I only use it in first gear. Thanks.

I had the same on a 9u D6 30 years ago. I started by taking the plate with the lock pins that are actuated by the clutch lever off the side of transmission. Hoping to find something simple like a bad spring. Found nothing looking wrong. Cleaned it all very well and the pins all moved as they should. Put it back together, and never had any more trouble. So I assumed just a very small piece of crude that kept the pin from moving with the spring pressure.

I have never worked on a D6 B so it may be different. But as I understand the back end was not changed much until the D 6 C , so I think the B would have the gear locking pins, that are actuated by the clutch lever. If like the D6 u series, it is much easier to take plate off the side than to remove the whole transmission.

The interlock problem you describe is likely caused by linkage wear. I had the same issue with my D6B. Clean the linkage and see where the "slop" is. Minor slack can be adjusted out.
Craig
 

Ray54 wrote:

I had the same on a 9u D6 30 years ago. I started by taking the plate with the lock pins that are actuated by the clutch lever off the side of transmission. Hoping to find something simple like a bad spring. Found nothing looking wrong. Cleaned it all very well and the pins all moved as they should. Put it back together, and never had any more trouble. So I assumed just a very small piece of crude that kept the pin from moving with the spring pressure.

I have never worked on a D6 B so it may be different. But as I understand the back end was not changed much until the D 6 C , so I think the B would have the gear locking pins, that are actuated by the clutch lever. If like the D6 u series, it is much easier to take plate off the side than to remove the whole transmission.
 

Well I got this far. Took the plate and linkage off the right side to look at the 4 plungers and springs. They look ok.

I'm having a harder time shifting from forward to reverse and opposite when working. The popping out of gear doesn't happen very often, but quite frequently the F-N-R lever is locked solid when I stop to change directions and I have to play with the clutch lever to get it to free up.

I will clean the pins and springs and put the interlock shaft cover back on, then see if tinkering with the linkage adjustment does anything. The manual gives one exact length for the interlock linkage length and that is spot on, but I guess it could be due for a bump one direction or another.

This mechanism, like everything else, is in such a NOT fun place to work on it.

Any other ideas or suggestions?

So after inspecting the interlock plungers and making sure the linkage is correctly adjusted, finding no smoking gun, I adjusted my operating technique. I have found that pulling back on the clutch lever slightly and hitting the brake pedals will free the F-N-R lever to shift. For now, this works. Broke my blade cable this past weekend so now I get to learn how to replace the cable.