Yes you will need to open the diff to take the C-Clip off that side and pull the axle out. I would suggest replacing the seal too and it wouldnt be a bad idea to just do both sides now. Otherwise if your other side has a problem you get to do this all over again.
Here's a write-up that will help you a little. It's not for bearings, its for the seals, but the disassembly is all the same.