Thanks, Rusty. It's a big block, so I won't have to worry about the distributor getting caught up on the firewall.
I start my 4 day weekend today, so I finally have some time to get out to the shop and pull it out. Who knows what I'll see, but I'll keep the thread updated.
Before I trailered it to the shop, I added some fluid so I could drive it onto the trailer. I was pleased to find that the transmission engaged in all gears in a good, solid fashion. I felt safe to take it around the block to see how it shifted. Felt great, just like it did before it puked out all of its fluid and started slipping, and no leaks. So, I dunno what's up with it, but I'm going to drop the trans anyway to have a look and at the VERY least, replace the front seal (possibly the pump/gaskets).