Douglas Spencer

I have a 2004 z71 with the push button 4wd. It wouldn't go into 4wd so I took it to a shop and had a diagnostic test done and we determined that the transfer case was bad because it seemed when we put the truck on the lift and locked it in 4wd the rear locked to the transfer case and the front locked to the transfer case but they did not lock together so I bought a used transfer case and installed it and now it's like the transfer case is in neutral and the truck doesn't even move but you can twist the rear drive shaft and the rear tires move. No lights on on the selector switch and it says service 4wd. If anyone has any ideas to what is going on it would be greatly appreciated.