hi Jim,
the lube in the shaft ball bearings may be dried out,
you can access it via the side cover in the photo,
use 90 deg. screwdriver and a drop or two only of
Triflow will free it up.
http://www.k4eaa.com/vfo.jpgnot sure about the nut for the vfo, I would try
the above before removing the vfo.
73 james