I have a 1998 Chevy k1500, my 4x4 has not been working, I thought it was my actuator motor, but I took it out and kept it plugged in and when I push my 4x4 button it engages and comes out. I tried to manually push whatever it is that engages the gears inside the axle, but nothing pushed at all, I was hitting solid metal, no movement.

Does anyone know what this means exactly?