I am pretty sure that the 1500 is very similar to the 2500 and 3500. To change seal and U-joint. You will need to pull off caliper,rotor,wheel bearing, and then slide axle out on both sides. When I have done this job, I put a seal in both places(sides). I had to remove carrier, and center axle disconnect. I used a long piece of pipe and seal driver. I drove seal in from opposite side. I slide the long pipe in Pass side of truck all the way to drive side seal, and then reverse procedure. Sounds like a lot of work, but it was not bad at all. Go VERY easy on those wheel bearing as this is the most expensive part if you ruin it.
I back out wheel bearing bolts 2/3 of the way. Then place socket over bolt head and use my Snap-On air hammer to push the bolt, which pushes bearing out. Works VERY well. I rarely ruin a bearing when doing it this way.
Good luck!!
Dave