need help with 4x4 problem quick!!!

ok i have a 1996 chevy c/k 1500 4x4 and it wont seem to work in 4x4 reverse going down the road where i live all three four wheel drive selctions work but it just got stuck in my back yard and would go in reverse and just spin the back wheel and the front would not spin at all i need help on this problem does anyone have suggestions?

Most likely one of these items or a combination.

1. Front axle actuator
2. Signal from the t-case to the front axle actuator
3. Something broken in the front axle