They hold up under water pressure in engine blocks so I don't
see why it would't in the yoke. Do you have the slip joint
out? Is there any evidence of the old one being swagged in?
If so, then it might be difficult to get a properly sized
freeze plug in place past the dimples.
If it were me, I'd put the proper size freeze plug in place
if I could get it past the dimples. Then set it and fold over
the dimples a little more. I'm sure that's the way the
original one was installed.

Kind of unusual to be missing that grease retainer plug. One
would really have to work at it to remove it. Possible that
someone removed it to clean the yoke and couldn't find or fit
a new one in place so they just decided to leave it. You never
know what these trucks have been subject to after 65 years.

DG


Denny G
Sandwich, IL