Posting follow-ups as a new question doesn't work here, because posts are not threaded by user, so this post has no context to your other. https://www.fixya.com/users/george-hausauer
Your 'Testimonial' to Steve Pack was not too gracious for his help;
Testimonial: "This is useless. I don't need a parts diagram. I already have the new spindle assembly. I want to know HOW to get it apart. Thank you."
It would have been better to click the Comment Box below Steve's and and say "Thanks for that, I have a new spindle, do you have any idea how to take it apart"? We do this Expert thing for no pay, and it is often a thankless task. I deleted a post last night for a similar retort to my previous help.
If I was second guessing Steve's answer, it was to show you where the fixing screws are. I see three in the nose and one, an allen screw hiding deep inside the chuck that fixes to the end of the spindle. There are very few others. There are two videos here that may help, all models from a company work to a theme.
Or take the drill and new spindle to a Milwaukee Serve Centre and have it done professionally with a warranty.
Or, you can phone Jack's Small Engines and ask.
Good luck and have a great day.