I have an 01 4 door lt and I just changed mine last week. Looked the same as yours. That top washer looking thing is the nut. It's threaded. Put a pair of vice grips on it and try turning it. Mine came right off.That's why I changed mine. Thought the nut was missing.

 

There is supposed to be a nut on top, could the top washer on your set up be threaded?, thats kinda what it looks like, I can't imagine it staying together if it's not.

 

Yes, the top washer has a threaded tube that goes into the bushing. I just took my large vice grips and it came off. Some wd40 would have helped but I was out.

 

Who wouldn't! lol