The only shop manuals I have right now with diagrams of those are the '67 shop manuals, but they don't show the T-19, only the T18. However, I believe they're close enough for you to get an idea of what they are. Here are two diagrams I just scanned for you.
In this one, you can see the interlock plungers and interlock pin, which look like what you're describing:
The second one was too large to post, so here's a link:
http://www.fordification.com/board/NP43 ... gram02.jpg
Hope this helps...good luck!
