Can seem a never ending job tracing noises. Every car I have owned has had some annoying internal noise eventually traced and cured. Dealers are usually not much help because they don't have the vehicle long enough to spend the time on it. You could check the seat belt stalks because on mine the passenger one was noisy where plastics were rubbing. A piece of sponge rubber has cured it. 2007 TD4 SE Manual
2014 TD4 HSE Auto