Rear pinion seal?

Hey all, my rear pinion seal is leaking. I'm going to be changing out my rear DS u-joints tomorrow afternoon and was thinking about taking the seal out while in there. Is there any special tools needed? Torque pre-load on the yoke that's specific? Any crush sleeves involved that need to be replaced when taken apart? I don't want to toast my pinion by taking it apart and putting it back on improperly. I can't afford gears since I just dropped 900$ fixing the front end! Tnx


EDIT: 1998 GMC Jimmy 4x4 4.3l

I believe the manual says to replace the crush washer. I have changed many of them and tighten them until a long 1/2 inch ratchet will just stay straight with the axle without falling. Basically you want them tight but not to tight.
Don't just impact the nut on. I never had any problem but do what you want.

First mark the pinion nut and the threads with a good marker or something, and count the threads that are showing, I also count the number of times the nut takes to turn off the thread. Undo the nut, pull the yoke, change your seal. Install the yoke, put the nut back on and tighten it down the same amount of times it took to get it off, align the marks, and your good to go. It has to be close, if its too loose, you'll know....eventually by the noise.