Wranglers don't have full time 4wd. Ours is a robust system that locks the front wheels to the back via the transfer case. This means that both a font wheel and a back wheel must turn. The system can bind up however on pavement as invariably one wheel will make more revolutions than the other due to turns. This is not an issue off road where tire slippage can prevent bind.
Ultimately its only in these low traction or low speed off road situations that you want to use your 4wd, and not on the road. So you should only switch into 4wd when needed or "part of the time" of your total driving experience.
Edit: guess I type slow