Chevrolet Repair: 4x4 problems, vacuum line, chevy 1500

Question
i have a 96 chevy 1500 4x4 the transfer case kicks in but its like the gears or the lockers wont ingage my front drive shaft turns but the axels wont turn i checked the actuator and it does push out i pulled it out and pushed the fork in till it stoped it pushed in and came back good so why isnt my 4 wheel drive working need help bad thanks

Answer
Is this an electronic 4wd of a vacuum assisted.  If it's vacuum assisted the vacuum switch on the transfer case may be stuck, or the vacuum line to the front differential may be broken somewhere in line.  If it is vacuum assisted front diff try pulling a vacuum on the front diff to see if engages.  If it's electronic you may have an electrical issue to the front diff switch.
Jimmy