New seals straightforward. Seals and bearings also, but check backlash before and after. You may have started with a quiet fd, with more backlash than specified. Which is fine.
You do need a couple of special tools. You can make the support plate with the hole in it.
Shims and belville washers can be bought, but if the backlash you have with the original shims is as per old one, or closer to spec, don't mess.