You know there used to be a Break Away torque that you could use to get an idea of the internal health. You use a plate with 5 holes in it and a large nut welded to the middle then using a torque wrench on the end of each axle you give her till the axle turns. If the cone is worn out and hanging up or the friction plates (clutch type) are worn the axle will turn easy. You have to lock the pinion yoke, and not by putting the tranny in park which should actually be put in neutral. The problem is I can't remember the break away torque but I think it was 150 ft/lbs.
