Hub rattle

My passenger side hub is rattling around and stops when I engage the 4x4 while in motion.
I got 2001 excursion a month ago and I am trying to get it drivable. It's my 1st PSD!

Both hubs are seized up but 4x4 will engage. Not low obviously.
PO never used 4 wheel drive.
Can I just pull these hubs and replace them or do I have a bigger problem?
I know if I use an aftermarket hub I lose the vacuum feature or 4x4 on the fly.
Can I rebuild these?

I plan on this fix during the break job it's in need of.

Thanks everyone. I'm loving all the help I finding on here.

This is prob an easy fix. I keep digging through the threads.
These look easy to remove. I just don't want much down time when I park it for repairs and want all the parts I need before I start.

The auto lock is nice but for the cost of new vacuum hubs from ford will outweigh the convenience in my opinion. Order yourself a set of milemarker stainless series manual lock hubs and be done with it. Lock them when the first snow flies and unlock them when temperatures reach above freezing for a week straight if you're in an area where there's snow in the winter. That's what I do and I don't have any issues. Other than that if I'm going to be driving into something I think I may need them for I'll lock them before I start off to there. I.E. muddy field or in the woods. If they're locked it's quite evident and you know they are even in 2wd. They'll click when you turn, so you know to unlock them. Takes about 5-10 minutes each side on the superduty chassis.

Good point thanks for chiming in. I've had manual hubs on a truck but it's been years. That truck had manual shift too. So driving around with them locked and not in 4wd is ok?

Yea. It's going to keep the front axle shafts turning but it won't detonate anything. A minute amount of added wear on axle seals but nothing major.

I also lock em upon first snow and use 4wd as needed... Then sometime in spring when I remember I unlock em

Thanks for the help guys. I got some OE hubs off of parts geek. They work great. I had to beat on the old ones quite a bit. They were rusty mess and the brakes got done too.