94 4WD Problems

I have a automatic push button 4WD. When I put it into 4WD high or low I can hear it engage. I accually hear the gear go clunk. But it does not seem like the gears are turning. The Front tires do not turn. I know because I was in snow and someone was watching. Can anyone help.

Is the rear wheels locking and going into posi? It sounds like a vacuum problem. If the front hubs are not locking, then I'd check the actuator for locking the front hubs which is under the battery tray. Otherwise check all other vacuum lines that involve the four wheel drive. I only had this problem when GM performed a recall on that actuator.

I have this exact same truck, and exact same problem, please let me know if you find a solution and I will with you too.