Probably the same as on my 6-14 3-speed gearbox, using labyrinth type sealing system. Cheap, not supposed to wear that much, poor sealing materials available at the time. The helical grooves cut into the tailshaft housing were supposed to provide a tortured path for the oil, along with the centrifugal force of the spinning shaft and force the oil back into the case. Probably worked okay for the thick 600W gearbox lube. See what problems are on our water pumps with the square section graphite impregnated rope that you are expected to cinch down every once and a while (without going too much, eventually wearing into the shaft).And they still leak some, because water is thinner than 600W.

Where Are You From? Orygun

Do You own a car built by Durant? 1930 6-14

That’s kind of what I was thinking. I probably overfilled it and too thin of lube. Ordered some 600w but it was dry so I put in some gear lube temporarily. Slings it all over when running lol.

Where Are You From? Glencoe mn

Do You own a car built by Durant? 1928 star R