Door Check problem.
 

Long story short, I was a dip and destroyed by passenger door on a tree.

I have since put a new (well used from a junkyard) door on it and the only problem is the door check is not working correctly. Even with the crashed door still on the truck it functioned correctly, aka going in and out. I took it off when installing the new door and now the arm doesn't slide in and out of the assembly. It's not a pricey part and I really don't have a problem replacing it. However its really pissing me off. Is there some sort of trick to unlock it or something?

BTW this is the part I'm talking about.
http://www.dormanproducts.com/itemde...SEName=924-932

When I replaced mine, I couldn't budge mine by hand if that's what you mean?