Didn’t seem super clear from the article but is this even a high/low system? Electric motors can spin at high RPM. So why would you need to shift the system. Just install the gear reduction to save the motor at crawling speeds and then let it run at a higher speed on the highway. And if this is the case just do portal style boxes at the hub. Doing it at the motors will add stress to the axles. But I’m just a shade tree engineer.