How hard is to switch gears in the transfer case?

Not too hard!  I did mine about a month ago, I had to buy a new puller to get the bearings and gears off, but a $15 GI Joe's special did the trick.  To put the bearings back on, I put the shafts in the freezer, and heated the bearings with my heat gun, and they just slid together with finger pressure.  I think it took me about 4 or 5 hours all together.  But I'm slooooow!  

D

It took a friend and I about 3 hours and a gear puller.  We used a deepwell socket and a piece of wood to put the bearings back together instead of the freezer trick.  It's still running fine so I guess we did a good job.

Just remember, if you go with the larger gears and need to check T-Case clearance, check BOTH sides.  The instructions I had only showed them checking one side.  I pulled my case back apart two times trying to figure out why it was locking up when I bolted everything together before I figured out what was wrong.  Yea, I'm a little slow sometimes.