I changed the fluid in my diffs and transfer case this weekend, and thought I would answer my own question here in case anyone down the road is searching for the knowledge.

The front and rear differentials use a 10mm hex head (allen) for the fill and drain plugs on both.

The Transfer case plugs use the 3/8" rachet extension square.

One more tip--the diffs hold a bit more than the manual says. I originally bought 3 quarts of fluid, but ended up needing about 3 1/4 quarts, so plan accordingly!