1. Stop using WD40 and start using a real penetrant. WD40 might be fine to stop your gate hinge from squeaking but it don't do Shiite on rust and corrosion. PB Blaster or Nuts Off! work. Working on axles, I go through two things - the "pretty boy" and rubber gloves.
2. Dude you need to use an impact. Or just hammer on your breaker bar. Or use an airhammer to loosen that biggun. :evil: Or a brass punch.
3. Check out jeepsunlimited.com - excellent stock Jeep tech. All of your D30 questions will be answered there.
Best of luck with those tricky "threaded fasteners,"
Bob