have you read the brown wire article here yet, kinda sucks cutting wires but its an easy fix for now, run a switch toggle style to disengage a4wd, you can still go to a4wd if you flip the toggle, and not loose 4 hi/ 4lo problems usually accure from useing them for reasons they are not set up for, like hard off roading in a stock expy, nothing is set up for the pounding it recieves, till modified with lift or am shocks, there nothing more than a family happy SUV. i did alot of damage off roading mine and takeing it places it didnt belong, 15 miles off road with a few jeeps, didnt work out in my favor, really tore things up bad, if they are set up for there purpose they are great, if you want to full a 40 foot camper, thats what they make super dutys for, its a matter of knowing what your getting into, like i said mines not huge, but its capable of alot more now than when it was stock, and i know my limits now, and what it can and cant do