So here's the result of that "crack"...
I am replacing the diff cases with the Integy alloys. I would've preferred FLM or RCM, but Integy is literally the only MFG making alloy parts for the MMGT. They should still be stronger than the plastic ones, though.
@Mothman: The GS is working well. In the pictures below you can see that there is no evidence of "slinging" in the case. Just more migrating. This is the front diff case (as you can see) which had less GS put on the gears relative to the rear diff case (which is in the slideshow above). The only place I noticed any slinging after the run was on the center U-joints, which don't have boots on them (yet). The dirt/grass would would get stuck to the GS on the U-joint, and then be flung off later, taking some of the GS with it. This will be avoided when I get the other two Revo CVD boots.