A system is disclosed for ensuring a properly aligned position of a pod door (22) within the opening in a pod shell (24) upon location of the pod at a tool load port. The door positioning assembly including a cam (44) affixed to rotating latch hubs (28) of a pod door latching assembly (26), and a cam follower (48) mounted around each of the cams (44), which followers include arm portions (52) that extend out toward an edge of the pod door (22). When the pod door (22) and shell (24) are separated, the arm portions (52) are held in a retracted position completely contained within the footprint of the pod door (22). However, upon rejoining the pod door (22) to the pod shell (24), mechanisms in the port door rotate the latch hub cams (28). Cam (44) rotation causes translation of the arm portions (52) of the cam followers (48) so that the ends of the arm portions (52) extend out beyond an edge of the pod door (22) and against a surface of the pod shell (24). In their extended positions, the arm portions (52) maintain a desired vertical positioning of the pod door (22) within the pod shell opening.Moreover, as the arm portions (52) remain in their extended positions after the pod door (22) is coupled to the pod, the positioning assemblies prevent the door from saging downward in the pod shell opening as a result of its own weight or as a result of a shock or jolt to the pod.