Difrntal mount bolt. A threaded rod with a drive head (such as hex, 12 point, torx, etc) on one end used to secure the Differential Housing Mount 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 to it's mounting point. Leaf Spring Shackle Bolt. Suspension Crossmember Bolt. Housing. Engine Cradle. HEX FLANGE HEAD. Leaf Spring Shackle. SUSPENSION crossmember.