not that difficult, but I believe the rubber rings that go around the dial have been discontinued by Isuzu. likely you can get them from Toyota or Suzuki.

there's also a pair of gaskets that go between the hub body & inner hub (bolts to the rotor & holds the outer bearing). they should still be available, I have the part # somewhere.

good Aisin hub info:
http://www.off-road.com/toyota/tech/aisin/index.htm
http://myweb.cableone.net/bcanderson/trooper/Manual%20Hubs/Manual%20Hubs.html


2.6 Trooper
2.0 Impulse Turbo