There are 2 schools of thought to this . . . some say the diff carrier has to come down in order for you to remove the bolt, and others say it's not necessary. Honestly, I've only glanced at mine and haven't really stared at it long enough to figure out if there is enough clearance to get the bolt out without 'major surgery'. But if you're just replacing the nut, I don't see why you'd have to remove the bolt. Other than that, you should be fine as long as the whole assembly is completely suspended and you've unloaded the tension on the coil spring.