If you want to outsource the gearboxes, the best way is to take one down to a large power transmission/bearing supply house, and have them match it up. Unless they recently changed, Ryko puts their data plate on everything, so getting a model number isn't doable anymore. I'm guessing that what Ryko does, like many other manufacturers, is spec out something slightly different on the box from its manufacturer, and then have it available only through them. Sometimes the spec is meaningless, like a seal for high temperture. A little investigation can yield some nice savings.