I bought my Demco Excalibur in 2004 also I have taken it apart twice to clean and lube it and lube the pistons and locking mechanism externally every year. When you take it apart you can inspect the parts for any wear or damage. I travel on a lot of dirt and dusty roads and fine dirt gets into the locking mechanism and can cause wear and prevent it from locking I have about 100k of towing on it and it still works fine. If you haven't done this already I would do it now just to inspect the parts seeing you are concerned and have asked the question. It is an easy job and will give you peace of mind.