Well anyways, I tore apart the transmission. Found the pump has a broken gear, but it still spins, so it clicks. Also it won't drive forward in any gears because the "Forward" clutch pack is completely stripped. Every one of the little tabs that the clutch plates have is completely stripped out. That explains the metallic looking fluid with shiny swirls in it.
I combined my old transmission clutch packs and valve body with all it's upgrades, into the newer transmission housing. I used the Low/reverse planetary and housing from the newer transmission. Put my old pump, and reassembled it all. Drove it around today, shifts perfectly, no delay in reverse, no shift flare, perfect. I even get a nice solid shift into overdrive, before you never knew it was shifting into overdrive unless you watched the tach slowly drop.
When I say my "Old transmission", it's really a 192,000 mile tranny but it was rebuilt about 35-40K miles ago, and actually looked brand new compared to the "newer" one that's only 96K miles.