Check where the cable disapears through the bulkhead. Sounds like something has hooked up.
Or the reason why it came off in the first place may be because it has started to seize. New one called for me thinks. You can try lubing it, but as the sheath is teflon lined, use only silicone grease. I don't think it will last long though as the inner cable will have carved itself a nice little channel in the lining and that is where it will be sticking.