I have a '14 S85. Drive unit #1 failed and left car inoperable. Tesla replaced with drive unit that makes humming sound above 38 mph. Been to SC 4 times. One tech hears it. another claims he hears nothing. Diagnosis was I need new tires. $1400 later sound is still there. Went back again today. They recorded the sound and "sent it to engineering to see if it was a operating within design". I find it impossible to believe that they will come back and say anything but that it's fine. Their drive unit is notoriously defective. They have given me a defective replacement after my first one failed, and they try to act like nothing is wrong, like I'm crazy. Does this company only respond when you sue/get the media involved like the recent settlement with the Model X owner? I would rather not go to that extreme. I'd rather they just give me a non-defective drive unit. I used to think these guys went over and beyond for customers. I now think it's like any other company watching their numbers for Wall Street. Looking for any advice from the great members of TMC. Thank you.