Why is my 2012 Porsche Cayenne Turbo grinding on tight turns and vibrating in reverse?

We had a 2012 Cayenne Turbo in that ground on tight turns and vibrated in reverse. The grinding came from worn transfer-case clutch packs. Collapsed engine mounts and a split upper torque support caused the reverse vibration. We replaced the transfer case and all three mounts, calibrated the AWD system, and road-tested it.