Rear end question

The reason why you cant find a torque spec for the pinion nut is that the nut is tightened only so far that the crush sleeve between the 2 pinion bearings is compressed enough to correctly preload the bearings. The preload is then measured with an in. lbs. torque wrench by putting a socket on the pinion nut & measuring the turning resistance if the pinion.
This has to be done with the diff carrier out of the axle. If the crush sleeve is compressed too far, resulting in excessive preload then then crush sleeve has to be renewed. it is not reusable.
The method I use to tighten the pinion nut is a socket on a long breaker bar while holding the pinion yoke with an equally long holding attachment, tightening the nut a tiny amount at a time until the correct preload is reached.