Well I had some issues with my tractor and it has been down each of the past 2 winters
When the bolt came out this time punched a hole in the 4x4 case that I could not braze up this time. Got a new case and put to together and it made a gear noise, bought both gears for the case, still made the noise. Ran it or a while without the 4x4 gears in the new case, no noise. Old case new gears OR old gears, no noise. Ended up the the 4x4 case was out of spec causing the gear in the tractor and the gear in the case to mesh too deep. A 1/32 gasket fixed the issue.
Hopefully everything stays together this time around.