[jt2190]

I strongly suspect that they used oil, not grease, so they could flush the dirt out of the gears, and that this would have been done very frequently.

[Animats]

You need tacky grease for open-air applications where centrifugal force will throw oil off the gears. Like this stuff.[1] I use that on open gearing in Teletype machines.

[1] https://www.lucasoil.com/product/red-n-tacky-grease/