I fixed a dumb mistake I made with setting up the linkages on the transfercase and it looks like mine is going to be just fine. Offers self a small round of a applause.
After that, I decided to sit in my HMMWV during an absolute downpour to see where it leaked. Naturally, water comes in through the vinyl window that has a large hole in it, but aside from that, it seemed like the only major spot was the grommet that that washer fluid pump wires pass through. That grommet is way undersized for the hole-despite being what came with the original pump. So, I either need to find a larger grommet or use some RTV to seal it in. ...or I could just let rain literally pour in on top of my foot.