Abstract: A reversing mechanism for an overhead door opener is described. The reversing mechanism includes a channel-form trolley track. A centrally positioned longitudinal slot extends for the length of a bottom of the trolley track. Side openings are provided at a first end and the second end of the trolley track. A trolley plate is positioned in the trolley track with a control arm edge extending through the slot. A chain/cable return guide having an axial chain/cable receiving passage is secured to one of the opposed faces of the trolley plate. Channel engaging guide blocks project from opposed faces of the trolley plate to engage a top and the bottom of the trolley track thereby preventing the trolley plate from being withdrawn through the slot. A chain/cable is extended through the axial chain/cable receiving passage of the chain/cable return guide, looped into the trolley track from the first end and the second end and secured to the trolley plate.