Pinion nut torque, and preload are determined by a crush sleeve, or pinion load (front to rear) at the (pinion) bearings. If you're not pulling the ring (differential) out, you can't use nut torque or preload as a guide. You really need to feel the previous load on the yoke as it revolves, and keep that as a minimum. The trick is to "sneak up on it" before you put too much preload on the bearings. I usually (simply) mark the pinion threads to the nut B4 taking the nut off. Then after your new pinion seal is in, you tighten the nut up to that, and feel preload/play. There should be slight drag, with no binding. If you pass that point, you need to reset the pinion or replace the crush sleeve (R&R pinion gear).
