Differential - assembly and installation
The original ring gear (crown gear) was fastened to the differential with rivets. When replacing, the rivets must be either ground off or drilled out, and replaced with nuts and bolts. The heads of the bolts can be seen in the left picture and yes they are slotted...and they sit flush with the surface so there is no way to hold them but with a large flat screwdriver.
Here is a feeler gauge checking for 0.025" between the back of the crown gear and the thrust block. Luckily for me the space was just about spot on.

After this the differential assembly is placed within the rear case, with the right hand trumpet already bolted on. I slid the right hand rear axle in place in order to support the differential while placing the left hand trumpet housing on its suds and buttoning up.

All told not difficult, but these pieces are heavy; you don't want to drop them on your toe.
Here is the right hand axle trumpet. The thrust block is there to prevent the crown gear from being able to wobble, and the proper clearance must be maintained.