The document discusses signs of a failing driveshaft in an Audi A4, as reported by certified mechanics in Thousand Oaks. Unusual noises like scraping, squeaking, rattling or clanking may indicate a worn driveshaft. Significant vibration when accelerating from low speeds is another sign. A malfunctioning driveshaft can make turning the car difficult and impact its smooth handling. The driveshaft is prone to issues after years of use if it lacks proper lubrication. Owners experiencing these problems should take their Audi A4 to a certified mechanic experienced with the model.