Differential Check Bolt Stuck....Ideas?

260z....differential bolt for checking the level is stuck. I've tried everything but that square bolt sucks and, of course, there is that metal bolted to it and the bushings on the frame, so a combo wrench is really the only option. I've tried an air hammer to loosen it, 1/4 can of PB Blast, a hammer and a huge combo wrench. It hasn't stripped out yet, but getting there. Ideas guys? There's no room, and even with leverage it won't budge. Is torching a bad idea on the transfer case?