According to the Service Manual
I checked my official Ironrite service manual (thank you again Austin and Venus). You would use 2 oz of Model 890 Oil in your machine. Part number S576, as opposed to the S575 5 oz can of Ironrite oil. The book doesn't give any further explanation as to the weight of the oil or if there was any difference between the two part numbers. Assuming when the machines were new, all gaskets were fresh and didn't leak.
What I would try is cleaning out that gearbox with a few sprays of non-flammable brake cleaner for cars. Then use a few sprays of a lightweight white grease to keep the gears running smoothly, and not have the machine leak.
An additional note, again per Ironrite, Machine Gives Shocks.
A small amount of electrical leakage will build up in any electrical appliance if it is kept in a damp basement. This is given off as a slight shock at times. To overcome this the machine should be grounded or the operator work on a rubber mat or rug. However, in case of hard shock from any appliance it should be checked by a competent electrical mechanic.