Sudden vibration/noise in the cabin. Transmission mount shagged! Place jack under transmission pan to support transmission (use block of wood between jack and pan to distribute stress on pan). Remove cross-member (4 bolts, 14mm) and broken mount under rear of transmission. My mount was so corroded that center bolt (15mm) did not even need removing. Remove shagged mount, screw in new mount ( aftermarket, from Volvo) Replace cross-member/transmission mount assembly. done.