Difrntal mount bolt. A threaded rod with a drive head (such as hex, 12 point, torx, etc) on one end used to secure the Engine Support Rod to it's mounting point. A threaded rod with a drive head (such as hex, 12 point, torx, etc.) on one end used to secure the Differential Housing Support to it's mounting point. FLANGE. Housing. Engine. Restrictor. Strut.