Haha Just did this on my R/T. When I had the tires replaced they shop found it. I got the part for around $12-$14 from autozone. It took me about an hour or so to swap out. wasn't too bad.
1. Mark the bolt, drive line, and diff case so you get everything lined back up where it was. (not sure how important this step is but I did it so as not to take a chance.)
2. disconnect rear drive line by taking out the 4 bolts on the companion shaft (part that houses the U-joint).
3. remove the retaining nut and washer. (for this I had to ask the guys at the auto shop I use, they said Impact wrench. So I just set the impact gun to loosen and let it fly till the nut backed off.)
4. Use a sliding-hammer-puller tool to remove the companion flange and set it aside.
5. use a seal puller to remove old seal.
6. lube outside of new seal with a little diff fluid. Use a socket the same size as the seal and hit the ratchet side directly in the center of the hole with a ball peen hammer (round end) helps to ensure you keep the seal flat.
7. reinstall companion flange, bolt and washer. ( the FSM tells you to replace the bolt and washer with new ones and torque it to specific torque. The auto shop guy I spoke to said to just use the impact wrench to tighten it down. This guy has been doing it for years longer than I have so I trusted what he said. I tightened mine with the impact gun, at so far it's been somewhere in the 1500-200miles range without any problems.)
8. Reinstall drive line to original marked position.
a- I removed rear tires to make sure everything rotated freely (without binding) before and after the seal replacement.
b- you should also plan on draining/refilling the diff, as mine pissed out fluid until I put the new seal in. Also this will ensure the correct amount of fluid when you are done.
c- I used bundling twine to tie the rear drive shaft up by the fuel tank for this.
That's all I can remember right now but If I think of anymore tips I will let you know...
Just did this like 3 weeks ago.
2003 Durango R/T (sold)
2001 Quad Cab Dakota Sport (sold) Re-Acquired!!