Oil options for gearbox

Has anyone tried anything other then steam oil in their gearbox (20hp Stanley in my case)? I took the drivetrain apart and was surprised by the amount of crud on the bottom that needed spooning out. It only had about 3000 miles since the last time I did that. also, since a goodly part of it is animal based, does steam oil have a life expectancy before it goes rancid?

Herb

Yes sulfur free 90 Wt. gear oil.
Rolly

are you seeing any issues with the oil not sticking enough and parts rusting after it is parked for the winter?

If you want add a can of chain lube to the gear oil, that sticks like glue.
I do not have the car anymore, but if your packing at the baffle plate is good you should not be getting any water in that part of the engine. It’s easy enough to drain out the oil in the fall. If you have the copper jacket off install a drain plug, makes life a lot easier.
Rolly