A shackle pin split nut assembly for a shackle having a pair of aligned openings for receipt of a shackle bolt. The assembly includes a two-piece clamp having a first ring segment and a second ring segment wherein the ring segments rotate about a pivot pin between a closed and locked position and an open position. A first button is received in a recess in the first ring segment with a spring urging the first button outward. A first tab projects from the first button which travels in a slot in the second ring segment. A second button is received in a recess in the second ring segment with a spring urging the second button outward. A second tab projects from the second button which travels in a slot in the first ring segment wherein the springs urge the first tab and the second tab toward the closed and locked position.