This is how to replace a pinion seal. a 31 spline 8.8 with a Torsen limited slip was used for this demonstration.
Thank you to Tyler (0RangerEdge2) for taking the pics and helping out!
Total Time : 20 mins
WARNING: do not eat before you look at the pics, the guy in the pics is ugly...
Raise the vehicle and remove the diff cover if you are planning to change the fluid at this time.
Mark the driveshaft location on the pinion flange and the driveshaft flange
Remove the driveshaft bolts using a 12pt 12mm socket
Tie the driveshaft up and out of your way
Mark the pinion flange orientation on the diff housing
Mark the nut orientation on the pinion stud and the pinion stud orientation to the pinion flange
Measure the depth of the stud protruding from the pinion nut
Remove the 1 1/16" nut to remove the pinion flange
Tap the pinion flange off of the pinion
watch that you dont get sprayed with gear oil like was
Remove the pinion flange
Remove the pinion seal
Install the new pinion seal
Install the pinion flange making sure all the marks line up that you made earlier
Re measure the pinion stud depth and tighten the nut down until the marks line up
Re install the driveshaft making sure the mating surfaces are clean
Put the diff cover on and fill with fluid and you are good to go!
hope this helps!