One more observation:  The front race of the thrust bearing is not seated against the gear as it should be.  Is it stuck there or just happen to be sitting out in this photo?  If the drive were assembled with the race dropped down so that it was pinched by the step in the input shaft, that would explain all the symptoms seen in the photos.

 

This same scenario on the engine thrust bearing has caused grief to more than a few engine builders.

 

Tracy