Onward!
The first thing to know is making sure the TC is set in far enough. Every youtube video I have watched on these things says to make sure the TC is fully seated. You need to hear and feel three clunks as it goes in. If you don't and install it all the way, that's bad ummmm kay? If you don't, the pump will supposedly get seriously damaged and you'll probably need a new TC as well.
Next thing I learned, (well I learned it on the way out actually, but now it is a bigger deal going in), the tranny is too tall to be on the tranny jack all secure (kind of) and rolled under the van. I didn't have jacks that got the rocker panel high enough so the bell housing would clear. That sucks. I had to slide the tranny under the van using cardboard, and then rednecking/holding beers and watching ensued. Except nobody was watching. But I was definitely drinking.
So here's what I did. OSHA look away for a minute. I rigged up ratchet straps over cross members to get the tranny off the ground. I believe this is where there may or may not have been a clang of the TC falling out and hitting the ground. Then there was combination of jacks and straps and swearing and grunting. I finally got the damn thing on the transmission jack under the van.