manual windows

When I crank the window all the way down it gets stuck and the handle just spins. I have to lift the window up a little then it grabs and works fine. What keeps the window from going down all the way? I have the door trim off right now and have looked but can figure it out. Any help would be great. Thanks

 

needs new regulator

 

what he said

 

Ok thanks. I guess I was just hoping that there was an easier fix considering all the functions of the window work except it just lets the window down to far. Ill put in a order for a new one. Thanks again.