[Oblarg]

Originally Posted by Chris is me

This is a bit of a tangent, but looking at your specific design, maybe you could build a gearbox that straddles your rectangular tube? Instead of driving a live shaft, have a gear off the gearbox drive another gear bolted to the wheel. I feel like this might achieve what you're trying to do (shifting gearbox with CIMs over drive wheels) a bit better than the coupler solution.

That's a cool idea, but it'd be harder to manufacture and I want to be able to swap the gearboxes easily as well as the wheels.