Pretty sure the closest this transmission and frame have ever been to a Honda factory is the sticker on the engine. It's rubbish and probably a generic single speed cheapie that appears, or is soon to appear, on all self propelled mowers sold out of Aldi and K-Mart. That said it's probably just a matter of time before the whole gearbox becomes available on ebay for 20 bucks free postage out of china. Ive decided it's just now worth the effort repairing given that I also need to chase up a drive cog for the wheels. Will remove all that paraphernalia, slap the wheels back on and leave it as a good push mower.
Interesting exercise though and a good warmup before I tackle the other real Honda. Haven't looked at it since I got it 12 months ago so no idea why it too was given away. For some reason people keep giving me mowers. Probably trying to tell me something about the state of my front garden.