To add to the above, the stock thermostat is 180F. Don't use hotter.
Valve adjustments are critical and keep the exhaust valves from burning.
The transmission drain/fill plugs are on the passenger's side of the transmission housing. The transfer case has a different set of fill/drain plugs and they are at the rear of the case.
75W-90 gear oil in front and rear diffs. Go Wild if you wish and throw some synthetic gear oil in there for less friction. If you have the "G80" code on your firewall plate, you have a limited-slip rear differential and should use Dino oil along with LSD additive to keep the clutches happy.
Cooling-system-wise, I've had 3 Troopers blow out heater hoses, so that's definitely a maintenance item. The heater core hoses at the driver's-side firewall are Twisted Little Buggers who like to blow out with regularity. So if yours look sketchy, replace.
And Good Words above to heed, regarding the timing belt. This engine is interference-type, and valves will be crunched if the belt breaks.
Parts-wise, Jerry Lemond on this site used to work for Isuzu and has a good line on the really hard-to-find parts. JLEMOND is his username or
[email protected] Use all caps to make it easy on Jerry's old eyes.
Rockauto still carries many service parts and, if anything else, is an excellent place to look up part numbers:
RockAuto ships auto parts and body parts from over 300 manufacturers to customers' doors worldwide, all at warehouse prices. Easy to use parts catalog.
www.rockauto.com
Hope that helps and Welcome to the Planet!............ed