This shows the left rear trailing arm and suspension

obvious

No, this picture is not dark, it is the oil that is black. Although the oil is black the differential contained about

1/2 gallon of oil and no metal particles. Looking at the teeth and components everything appears good.
 
 

The two images below are the left and right flanges that were attached to the outside end of the ½ shafts. These flanges then bolt to the flange that is on connected to the wheel spindle in the trailing arms.

Unfortunately they are not the same. I guess someone has replaced something here?