Buy an extra Pinion bearing and grind out the inside of it so that it slips on and off of the pinion freely so that you can measure the shims a couple of times...DON'T PUT THE CRUSH SLEEVE ON UNTIL YOU HAVE ALREADY GOT THE WHOLE REAR END DEAD ON IN MEASUREMENTS. Make sure you have a couple of them already. Make sure your stang is as high in the air as it can be because you're going to need a ton of torque to crush that sleeve. I used in excess of 300lb ft of torque to crush it...Also, you're going to need a fairly low torque 3/8's torque wrench with adapters to I think a 23mm socket so that you can check the preload. Preload is how much torque it takes to spin the pinion, not the torque of the nut.