Before you screw the nuts out of the box, mark their position and count the turns when unscrewing them. They need to go back in the exact same position as they set the position of the ringgear.
Do one by one, this way it is not possible to overtighten one nut by a full turn.
Depending one your gearbox or combination of them, you may or may not have an o-ring on the outside of the nut, replace if present, otherwise use sealant, i had success with hylomar.
Also replace the o-rings below the driveshaft spacers, had one gearbox leaking from them.
If you do not have special tools for the nut, a broken of 90 degree snap ring pliers could do the job.
Rainer