I have a clicking coming from my front driver's side tire when I am in 4wd and climbing a hill.
I am guessing it may be the hub, how would I best diagnose this?
Thank you!

 

Jack up the front end and spin the wheel and see if you hear the sound.

I'd also consider a bad u-joint or issue with the differential.

 

Axle U Joint.
When my clutch went out in CO last month, I had this shop check the same click click noise from the drivers side.
YEAP!
bad axle u joint like I thought.
It does sound like a bearing going as well, but like PatHenry said, "jack it up" and check the wheel.

 

listen to the tcase too when you are spinning the wheel, could be a sloppy chain. If you suspect the wheel bearing is bad, never been replaced, just replace it. I suspected I had a bad bearing, tested it didn't seem like anything was wrong, couple weeks later it went out, it pushed on the rotor when turning sharp left and the brake pedal went to the floor.