Hmmm, that gets me thinking. I have an almost new tube of general purpose lithium grease, like the kind you use for bearings and whatnot. What if I cleaned the gearbox and smeared that on all the surfaces and put a blob in there, packing it in?
Really, I only need a solution that will "work", it doesn't have to be 100% proper, just good enough for a few hours of use every year for a couple of years. I would be happy with that