any sort of trailer bearing grease would probably work
I believe trailer bearing grease is unsuitable as it is too thick. It would be NLGI 2. Same goes for “general purpose” grease. That`s probably NLGI 2 as well. Based on my research (not any personal testing), greases used with success nowadays in the old direct-drive lower units are thinner, and so will be better at reaching all the areas in the gearcase requiring lubrication. For reference, greases that are popular for use in direct-drive outboard lower units are John Deere Corn Head grease and Lubriplate 105, which both have an NLGI certification of grade 0 (zero, not letter o), which is thinner than NLGI 2.
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