Not sure I am following what you are trying to do but I think you are asking about taking the cv joint apart?
Most of them do have a snap ring inside the cup that you have to take out then the cup will slide off. But I have seen a couple of 420 axles that there is a ring staked in place and no way to get them apart. I haven't worked on a 2018 so not sure what you have. But the one axle I came across that had the staked in ring in it that I couldn't get apart was on a 2011 with IRS
Most of them do have a snap ring inside the cup that you have to take out then the cup will slide off. But I have seen a couple of 420 axles that there is a ring staked in place and no way to get them apart. I haven't worked on a 2018 so not sure what you have. But the one axle I came across that had the staked in ring in it that I couldn't get apart was on a 2011 with IRS
