[nickd]

The big castelated nut has to come off in order to pull the axle out. Heat helps, plus a long steel tube over your breaker bar. Or an air impact if you have access. I usually remove the lower shock bolt (also a lot of torque) too. This allows the control arm to drop lower and gives more room to maneuver the axle out. Disassembling the axle to replace the boots is a whole other pain. Not a fun job!

Ps- No reason to buy a giant torque wrench. Just use a pipe of length 339/your weight and stand on it.