The LiftMaster 310-8004 Step Key (1/4 x 5/16 x 1-1/2) is an OEM replacement shaft key designed for select LiftMaster commercial door operators and gate operators. This stepped key locks a sprocket, pulley, coupling, or drive hub to a keyed shaft, transmitting torque and preventing slippage under load. Its stepped profile allows the key to bridge two different keyway widths—one side 1/4 and the other 5/16—so the hub and shaft can mate securely even when their keyways differ. Use it when servicing or rebuilding a drivetrain where the original key is worn, lost, or damaged to restore precise, reliable power transfer in sliding gate openers, trolley operators, jackshaft operators, and other LiftMaster drive assemblies.
Installation is purely mechanical: align the shaft and hub keyways, orient the wider step with the wider keyway, and seat the hub fully before tightening any set screws per the operator’s service manual. For safety, disconnect power, follow lockout/tagout procedures, and support the door or gate before working on the drive. Compatibility should be confirmed against your specific operator’s parts diagram or service documentation using part number 310-8004, or by matching the key’s stepped dimensions to the existing components. No programming is required; this is a direct-fit LiftMaster replacement for maintenance and repair of commercial and industrial operator drive systems.