Hey hey, it's (mostly) done! The truck is running and I've driven it around the block. The new (used) transmission works far better than the original.
The "mostly" part of that first paragraph is that I haven't been able to fit the second frame crossmember back into the truck. It's pictured in the photograph above—it's the piece running underneath the transmission1 between the two suspension mounting points.
In any event, I wasn't able to get the crossmember wedged back inside. I fully plan on putting it back on, but it's not a priority for today since it really only appears to be a rigidity thing. The first crossmember mounts about eighteen inches in front.
So there we have it. Easily 20+ hours of wrenching has netted me a working truck, sans a crossmember.
1 Yes, I first tried to remove the old transmission without removing the crossmember, since I knew it would be a huge pain in the ass to remove and replace. No, it didn't work. And yes, I did smash my kickdown linkage trying.
I dont suppose you have a flexplate access cover?
Why yes, yes I do. It's actually a flat piece of sheet metal that screws onto the transmission just below the oil pan. That's not why you're seeing the flex plate in that photo--I've actually got the transmission pulled away from the engine about an inch in this shot, and am trying to wrestle it past the crossmember before dropping it out the bottom.
--D
Oh and for whatever reason, Ye Olde Chilton's refers to that part as the "converter drain plug access cover," which absolutely did not give me the impression of an 18" wide piece of stamped steel.