[Just-in]

Rear diff is pretty simple.
On a level surface take a 3/8 drive ratchet. Open the fill plug on the diff cover. Put your catch pan under the diff. Open the drain plug with the 3/8 also. let er drain... Wipe all the metal sludge off the drain plug it has a magnet on it to catch all that nasty junk, take your time getting it clean.

Re insert the drain plug, fill the rear diff to the capacity in the manual I believe it's 2.5 quarts. another way to make sure it's full a little more old skool, fill it ti'll fluid runs out the fill plug, let it stop runing ti'll fluid is just below the hole then plug it.

hope this helps.