1949 - 1953 Passenger Car Shop Manual w/1954 Supplement
Assembly Number 5.
Remove speedo gear and fill ball housing with 1/2 pint gear lube.

I thought it depends on what transmission you have.
3 speeders don't have that pipe plug.

Car & truck use the same size ball housing.
Pipe plug or speedo gear, 1/2 pint of gear lube will suffice.