[John Arnold]

Not all double action truss rod nuts are fixed to the rod, causng the rod itself to turn. Some have a captured nut (Martin style). But in either case, the nut is not removable. My aversion to double action rods is three-fold.....broken welds, no easy way to lubricate threads, and the too sensitive function of the ones that work by having left-hand threads on one end. That doubles the rate at which tightening/loosening takes place. One design is more clever, having fine threads on one end and coarse on the other (both right-hand). This is the slowest adjusting of all. In that case, the only downside is that it takes a lot of turning to make it work, and may make you nervous if you don't realize that is how it is supposed to work.
Before you give up on it, make sure you are not in the 'dead zone', where nothing happens. Most double action rods have some play in the center position. It is the fourth reason I don't like them.....a rod with no tension on it can buzz. A properly installed single action rod is IMHO all you need. Proper installation means pre-tensioned so that it is never completely loose. The rod is tighened slightly and the fingerboard is trued flat. When strings are tensioned, the rod balances that tension to adjust relief.