I had to drop my diff and clean the years worth of sludge out of my oil pan and replace the connecting rod bearings.
Its not terrible...their are 2 or 3 fasteners that a complete PITA. Gearwrenches and long extensions come in real handy.
This is the write up I followed.
pulling the front diff - Toyota 4Runner Forum - Largest 4Runner Forum
Might not even be worth it unless you're wanting to do the lower end which even then the access to the crankshaft is pretty limited..keep us posted and good luck!