You're not going to like this answer, but it is nearly impossible to add transmission oil without pulling the whole transmission, removing the cam bars, pulley and wig-way, and pulling the cover.
These transmissions require 60-weight non-detergent oil, which is very difficult to find. Fifteen ounces (nearly a full quart) is needed to fill a dry transmission.
Question to you however - how much oil was lost? It is very common for the transmissions to leak when a machine is laid down, but they leak from the agitator shaft, which is essentially in the center of the transmission. When the machine is laid on its front or side, no more than half the oil can leak out. If the machine only lost say even an Eggo waffle sized amount while it was being worked on, it should be able to live without it. I have seen many that leaked far less than this while I changed a belt.
If you are bent on adding oil, I have wondered about inserting some through the top vent hole, but it's tiny and with 60-weight oil, I don't know how easy it would be to force it in there. You would need something like a zoon-spout bottle.
Let me know how much was lost - I'm curious.
Gordon
