Contrary to popular belief, your NP231 equiped Jeep will not suddenly self destruct if its driven on pavement in 4WD. Anyone who has been to Moab or any other places where slick rock (which is not slick but actually offers better traction than Asphalt) will testify that your drivetrain will not instantly go BANG. It will bind, handle like crap, make bad noises, hip and hop around and prematurely wear out, but will probably not explode. Im not recommending that you drive around in 4WD all day because its surely not good for your Jeep and its not designed for that, but its not going to tear it in half either.