Zach the explorer case you are thinking of is definitely automatic 4x4, our 97 had it. I hated it personally. I think my wife liked it because it would engage under heavy throttle in the rain and stuff, but I didn't like it because it was kind of rough. There is a brown or yellow wire mod that allows you to disable the auto4x4 on them though.
Well there is also the standard AWD case that came behind the 5.0L.
I'm pretty sure the expeditions were auto4x4 as well, but maybe I am only thinking of certain years. No matter since it wouldn't fit anyway.
On a very random side note, I always thought a fun project would be a 98+ ranger regular cab 4x4, with a built 5.0L auto with AWD case, lowered a couple of inches to look like a 2wd. It would be a fun sleeper anyway.
2006 F150 FX4 Super Crew - Bilstien 5100s leveled 2", 35" KM2s, 4.56 gears, Detroit locker, Eaton E-Locker, Traction Bars, AEM intake, Xcal 2
2010 VW Golf TDI 6MT