NHTSA Complaint #11462589 — 2014 CADILLAC CTS

I started to notice pulsation upon braking and replaced my pads and rotors, at the same time switching from winter wheels to summer wheels. The pulsation continued, and then I noticed a rumbling sound from the rear end that has grown increasingly loud over the past three days, and now it is accompanied by wobbling upon braking at speed. An independent shop today diagnosed it as a rapidly failing rear differential. The car has 70,000 miles and no accidents. As I understand it, the CTS-V version of the same vehicle has a recall for failing differentials that are the very same part that's used in these non-V models. The web is full of complaints from other owners of my model who are experiencing this same issue. It is a catastrophic failure part that could cause the rear end of the car to lock up at speed. Please address ASAP, thank you!