Volkswagen Group of America (Audi) is recalling certain 2021 Q7, Q8, Q5 Sportback, SQ5 Sportback, RS6 Avant, RS7, RSQ8, 2020-2021 Audi S6 sedan, Q5, A8, S8, A7, A6 Allroad, A5 Cabriolet, A4 sedan, A4 Allroad, SQ5, S7, A6 sedan, S5 coupe, S4 sedan, S5 Cabriolet, A5 coupe, 2019-2021 RS5 coupe, A5 Sportback, S5 Sportback, RS5 Sportback vehicles. The lock nut on the trailing arm of the rear axle may break due to stress corrosion.