The quadratrack unit is a full time 4x4 unit that uses a limited slip dif carrier in the transfer case.You cannot use locking hubs with the stock system as the diff will allow torque to the front axle which is unlocked. Milemarker makes (made?) an aftermarket part time kit that converts the diff to a part time unit. My guess is that somebody has installed one in your jeep. With the transfer case in the "unlocked " position, (the selector should be on the glove box) lock both hubs in and jack one tire up. If the tire/front driveline spins then you have a part time kit.