Front axle question

[smalltruckbigcid]

For a friend of mine. How does the front axle engage on a 97 yukon. His feels like its in 4hi most of the time but the lights in the dash say otherwise. Does anything unlock the wheels from the diff or does it pull that along all the time no matter what?
Thanks
George

 

[daleearnhardt01]

Driver's side side gear will spin all the time, passenger side axle is disconnected before diff

 

[smalltruckbigcid]

so is that what has to connect to lock the front in. He thinks it uses the heater style, that part heats up and locks the axle in?

 

[noJeepshere]

i think gm got rid of the heat actuated axle disconnect in 94-95 or so. when it breaks itll go to 2wd and stay there. i think your buddies shifter actuator on the t-case is broke. that happened to our 98 sub, it stuck in 4lo and pushing the switch would move the light to whatever mode, but no shifty. bad news, its an $800 repair.