thanks for the replies, right now there is slippage here and there so i'm just leaving it in 4HI until the snow is gone, just to give you guys an idea these are the major roads i'm talking about.

 

while you probably could drive easily in 2wd, you have 4wd, use it...better safe than sorry.

 

The only reason I'd use 4x4 on a road like this is if I was stopped and wanting to accelerate quickly or up a hill. Keep in mind you will have more overall control of the vehicle in 2wd because the front wheels won't be locked with the rear. It won't hurt the 4wd, but there is a decent chance it will help you slide into a ditch around a corner (front wheels want to slide on corners when in 4x4....)

 

This is my sixth 4x4; never really ever had problems with any of my trucks and that is by using some common sense.
If you need to use 4x4 for higher speeds, chances are you are driving to fast for the road conditions; you can't stop safely. Using 4x4 will help accelerate you and help you steer a little better but it doesn't help with stopping distances.
If the steering feels heavy, chances are you have too much traction to use 4x4.
Completely turn it off even going straight when it is dry, I don't believe the transfer case is either liquid or oil cooled; it will heat up quickly when there is a lot of traction.