RE: 1/48 gearboxes
They look kind of cheesy, but you gave me an idea.
I have a 1/48 Tamiya Tiger I with a ton of PE and other aftermarket stuff. I put it away years ago because I got so bogged down in the details, it has like 8 piece muzzle brake to give you an idea about how absurd it was getting. It might be a fun winter project to RC it. I think I even have metal tracks for it.