FINALLY, I got the pinion seal replaced on the differential of my 83 wagon. Ended up buying an electric impact wrench for $39 from Harbor Freight to loosen the pinion nut (torquing it back by hand wasn't as difficult as getting that sucker loose for some reason). After that, the only frustrating thing was getting the flange pressed in in exactly the right place so it lined up with the driveshaft. I used a crayon to mark the line-up marks before removal, but it's still a little tough getting the flange put back in exactly the right place. I love the way the Haynes Manual says things on the instructions for doing this job like "Remove the pinion nut." Much simpler than it sounds. All in all, if you are not equipped with an impact wrench for removing the pinion nut, ramps, torque wrench, crowbar, 2 14 mm box end wrenches, a 27 mm deep impact socket, a hammer, a block of wood, replacement gear oil, a puller, and a weekend with nothing else to do but lay under your car, I'd suggest having the job done at the shop. But, I did it myself which was pretty cool.