I'm not positive what the drive gear inside the Hummer box looks like but my guess is it is a solid chunk of gear steel. It shouldn't be an iss ue to broach it to 1.5 35 spline. And again like others stated, I don't think it'd be worth it. The stress that shaft sees is minimal compared to the outers. If anythink I'd be looking @ beefing the boxes and possibly the outer shafts.
