RC10Nick nailed it. You'll need to open the tranny case to make it happen. The Durango instructions are not the best I've ever seen, but once you've torn into the car once or twice you'll find they really aren't needed.
If you don't have it handy, here's a link to the Durango insert guide. This is VERY handy to have. I can't post an actual link, because I don't have enough posts yet, but you can probably figure it out.
www_team-durango_com/blog/2011/10/27/dex210-insert-guide/