I've had a slight "clunking" sound which I believe is the driveshaft because it has a lot of slack in it and I've read a few other cases where these cars experience that, and a constant "grinding" type noise from somewhere in the rear, possibly the diff, for quite a while now. I have it lowered on the Eibach Pro Kit and have the BMR adjustable panhard bar, so I was thinking maybe my pinion angle was off. I ordered and installed BMR adjustable upper control arm and mount and Eibach adjustable lower control arms. The pinion angle is right at -1 and the noise is still there but now with an additional rotational grinding noise. Sounds almost like an axle bearing or something and gets worse when turning to the right, which leads me to believe the left bearing is going out. I am going to adjust the angle down a little more to a -2, but I don't really think that will make the noise go away. Any ideas? 2013 SVTPP with 27k miles. I'm trying to avoid taking it in, but I think I'll be dropping it off at Ford Monday or Tuesday. Also, it doesn't make the noise when the car is on the lift and tires spinning freely and there is no vibration at any speed.