Transfer case
 

Are transfer cases the same model in 2000-2001 ? Looking to either swap one out or rebuild existing one ? Is removal difficult ?

Yup, same.
There are two models, the 242 (full or part time 4WD) and the 231 (part time only)

Raise all 4 corners on jackstands.
Put a trans. jack under the transmission
Disconnect front and rear driveshafts
Disconnect speedo and 4WD wiring harnesses
Disconnect xfer case shift linkage.
Drain the T-case
Remove the crossmember and trans mount so you can drop the trans a few inches to help reach the top bolts in the next step..
Remove the case nuts holding the xfer case in place.
Pull the xfer case straight back to disengage the transmission shaft. Careful it doesn't drop to the pavement.
Reverse to install.

In theory it's all pretty easy. I just did mine, however the 6 bolts that hold it to the transmission, a few of them have extremely limited access. I had to cut a few of my wrenches super short to get in there and a ratcheting wrench goes a long way. Also don't try it without a tranny jack, it's a freaking heavy. By itself off the truck it isn't bad but unless you're an ox of a human it'll be difficult if not impossible to lift it back up in place.

Also note if you don't jack up the truck as I didn't, put wheel chalks on all 4 wheels. Soon as you disconnect the drive shaft it'll roll free.