Possible to tighten spider gears on Ford 8-inch?

I took up some of the slack in a '66 era Ford 8" using the adjusting nuts
on
the main ring gear carrier. What I did was adjust it to where there's just
a
barely perceptable amount of "slop" between the main pinion and the ring
gear with no wiggle in the ring gear carrier and the whole thing turns
silky
smooth by hand.   However, there's still some slop in the rear end. I
assume
it must be in the differential or "spider" gears.  Is it possible to
tighten
these or once they're worn, is that it?

Does anyone make replacement gears/bearings for these rear ends?