Antique car gear oils

[Dave Sherman]

Looking for some input on differential and transmission oil for the '47 Lincoln. Old manuals are saying 90 weight gear oil for the differential, transmission calls for 140 weight gear oil in summer, 90 weight in winter. The transmission has an electric overdrive that shares the transmission oil. No idea if the transmission is compatible with GL-5 oils or not, so I'm thinking Redline MT90 GL-4 for the trans, and probably a 75W-90 GL-5 for the differential.

 

[Lubener]

I think you made some good decisions.

 

[PontiacHO]

Yellow metals safe is a must. Not sure about the diff but wouldn’t hurt.