Today Tesla service in Las Vegas stated they are not replacing faulty and noisy drive units. It was previously their position they would replace noisy drive units up to 8 yrs. This is my second model S. The first one a 2013 required 3 drive unit replacements in under 50k miles. My present car has 47k on it and the rear motor is making enough noise that anyone who rides in the cars back seat ask me what that noise is. I can also hear while accelerating while driving the car. Why has this policy changed?