Nothing is going to fall apart buy removing the pinion nut. LOL
Your only concern is that you check the pinion preload before and after you swap the flange over.
Many experience techs do this buy feel. If your not sure you will need a inch pound torque wrench to measure effort to turn pinion.
Normally this is done with the 3rd removed from vehicle to get an accurate measurement. (not turning axles)
If the axles are still removed you could do it in the car.
I'm hear if you have more questions.
