Found the Culprit!

Well it finally stopped raining so I was able to get out to the tractor today.

The first thing I did was to disconnect the tie bar and remove the top bolt on the bearing in the picture.  Reading on the tractor blogs that the bottom would drop out after I undid the bolt, I used a car scissors jack to hold it up so I could lower it easily.

This is the bolt I removed.

Immediately, all the weight was on the scissors jack so I just lowered it down in a controlled manner. Upon inspection, I knew I was getting closer because of the score marks on the shaft.

Something cause these score marks!

 Next step was to unbolt  the shaft housing from the axle.  After undoing the bolts and slowly tapping the housing away, two gear pieces fell out.  Eureka! The problem identified!

Two gear pieces fell out as I was removing the housing.

 Here is the gear with the pieces missing.  The bearing on this piece appears OK to me.

Damaged Driving Gear  Part  184.31.119

 Its mate also shows some minor damage and the bearing is a little rough.  I will probably have to replace both driven gear & its bearing.

Minor damage to driven gear. Part 184.31.115

Now I also need to find a friend with a bearing press and removal tools.  I also have to clean up the parts, make a parts lists of what I need (i.e. gaskets, bearings, seals, etc) and order them from someone online.