Which carrier do you have , mark the Nut & pinion Before lossening the nut so the torque can be matched back up , if it is a 489 carrier & would really try to get the bolt out Without removing the yolk if it is a 741 or 742 you can remove the yolk , no rollers will fall out
Penetrating oil heat & an easy out is the way I would try to remove it , or weld a nut onto the broken bolt if possible , the heat from welding will help loosen the broken bolt