Well, you could but the tranny in first through 4th gears, and turn the primary shaft by hand, and see how many revolutions the differential turns, and figure out the gear ratios. That sounds like a PITA, but it would be a direct way to find the ratios and see what tranny specs it matches. I've never done it, so I don't know for sure if it will work, but it's an idea. There has to be some other marking on it to tell, otherwise how would even the suppliers know?