The lathe, however, does leak oil, I have a feeling that it is from
the threading gearbox.

My Clausing leaks too, but from the apron. I'm wondering if this is a
common wear problem for the Clausings and what the fix is. I think on
mine, it has to do with the fit of the worm that drives the feeds and
its fit in the bushing on the tailstock end. My "fix" is to not use
power feed very often.

RWL