Good show! Generally, the pinion preload is set before the carrier and the ring gear is installed, but checking the total turning torque and retightening the pinion nut to get that figure is a good work-around. The first time the pinion preload is set, the crush washer is being compressed, so it's an incremental process to sneak up on the right preload. A properly set up rear end should last many thousands of quiet, trouble-free miles, but there are about a dozen ways to mess it up, and only one chance to get it right.
Jerry
