I have studied the parts diagram and notice there is a plastic tube inside the gearbox with slotted ends that serves as a gearbox breather.  In my cleaning up of this old machine, removing concrete like mud, I have yet to find where this breather vents to ambient outside air.

 

Could someone please explain where the gearbox breather vents externally?

 

Thanks

 

I remember looking at this when I rebuilt mine. I remember being puzzled by it and then going 'Oh, that makes sense..' Sadly, I'm struggling to remember exactly what I saw...

 

I seem to remember that the casing bolt hole is wider than normal and allows the air to go along the side of the bolt. That's all I can remember though! Sorry. Can you post a pic to jolt my memory?

Found it. As mentioned, the case breathes via a small passageway at the center case screwhead above the countershaft.