Does anyone know what type of gear oil goes in a 1970 40 hp selectric shift outboard? It is not 80/90.?

i know that the oil is of thinner viscosity but not sure how thin.Does anyone know what type of gear oil goes in a 1970 40 hp selectric shift outboard? It is not 80/90.?
type C premium gear lube is a ';special'; blend of 80w with the usual emulsifiers (to keep water in suspension) and rust inhibitors, plus hypoid ';high-pressure'; additives.





Use the type C -- those lower units and parts are hard to come by.Does anyone know what type of gear oil goes in a 1970 40 hp selectric shift outboard? It is not 80/90.?
Anyone one of these will work just fine. If there is a lot of slippage, use the 120 weight. A motor that old will not know the difference.
Type C lube ONLY