your front axle is not 'disconnecting' from your wheels. there is a free-wheeling clutch bolted onto the passenger side of the front diff. there are 2 wires going to a sensor within this clutch. you need to trouble shoot the 2 solenoid valves along with the vacuum system that operate this free wheeling clutch. more times than not, the solenoid valves stick open or closed or go bad altogether over time. the solenoid valves are mounted on the inside of the engine bay on the passenger side front fender just under the air intake from air box to throttle body. one is marked with a yellow dot and the other with a blue dot.