I want to clarify a few things as well as help out JMT.
First, I can tell you from experience that marking the pinion nut and threads is not a reliable or even a good way to re-tighten the pinion. A difference of 10 in/lbs could be as little as 1/16' nut rotation. It is amazing how fast torque goes up compared to nut rotation.
Second, and I think everyone has agreed, is to use a new nut. That eliminates the mothod described above.
Third, the FSM doesn't just state to tighten it to 160 ft/lbs and call it good. It actually states to check your pinion preload prior (which requires removing the carrier) and then try to match it + 5 in/lbs once you re-install the yoke.
I can tell you that a crush sleeve may or may not be reusable in that instance. But waht are you going to do if it's not, or if you overtighten it? If you are going to reuse the crush sleeve, fine. I'm saying you should have at least another one on hand in case the original is unusable.
Simply tightening it to 160 ft/lbs is only part of the equation. Even then, I don't like that as an answer in general. Tighten it to whatever it will take to get the proper pinion preload. If it's 160 great, but if it takes 210, then that's what I'll do. By not getting the correct preload you risk abnormal bearing wear or bearing damage which results in a new gear job.
I'm glad people have had success doing it the short way but the risk just isn't worth it to me. $5 vs. $1000. Your call. And I say that loosely because if you can re-use the crush sleeve and get it to pre-load spec, then great!
With all of that being said, most shops will take the shortcut because time is money and good enough is good enough for them. Not my preference though.
