I'm not familiar with the 500, but if you're talking about the pinion nut (#6) to replace seal (#8) I believe you're going to have to remove the u-joint.
The service manual for these things says to put the u-joint in a press, not sure about you, but I don't have a press large enough to get the whole UTV into, and the driveshaft isn't bolted to a flange like on a bigger vehicle, so we're going to need an alternate method. If you google how to remove a u-joint without a press several methods come up for you to try.
Sorry I can't offer you better advice, but let us know how you manage so the next guy has an easier time. Pictures are always helpful too.