What Bartamos says is correct. On replacing a yoke on a crush sleeve differential, I've seen some procedures calling for checking rotating torque BEFORE removing, then tightening the new yoke nut till the rotating torque is just a few inch-pounds above the original number. They also specify that you CANNOT back off the nut if you overshoot, and if you do overshoot, you need to install a new crush sleeve. On a differential that uses shims for bearing preload, it's much easier. You just tighten the new nut to spec, although I've seen specs up to 450 ft-lb (Dana 80's for instance). The issue with getting that much torque on a nut is being able to hold the yoke stationary while torquing. And DO NOT use an impact wrench.
You need to determine if you have a crush sleeve or a shimmed differential and proceeding accordingly. If it's a crush sleeve type, using a new crush sleeve and torquing a NEW nut to factory preload rotating torque would probably be your best approach.