They were due for replacement anyway ... You don’t want to over-torque the nut and alter the pinion bearing preload. For axles with spacers, you can gun the pinion nut down with an impact ...

When you replace a pinion seal, you also need to think about axle shaft bearings and seals because if the pinion seal is leaking chances are good all seals probably require replacement.

and retaining nut must be exactly maintained so that pinion bearing preload isn't altered. Pinion bearing damage can otherwise result, and that could ultimately require complete differential teardown.

Though the job itself is a dirty one, the removal and replacement of the differential ... you can burn up the pinion gear bearings. Moore got it right, of course, and the result is a quiet-running ...