Gearbox Assembly 1254834 Replacement part compatible with DDF453, BDF443, 6391D, and DF457D models. Includes 1 piece gearbox assembly for reliable power tool and restoration of drilling performance. Compatibility: Fits 6391D, DDF453, BDF443 drills ensuring seamless integration with existing tool systems for consistent torque transmission and operational efficiency. Long Lasting Performance: Constructed with grade plastic materials to deliver lasting durability under regular use while maintaining smooth gear engagement and reduced wear. Precise Engineering: Designed with exact specifications matching original equipment standards including part number 1254834 for accurate fitment and trouble installation. Use scenarios: a worn gearbox in a DDF453 or 6391D drill to restore drilling performance and torque. Maintain smooth gear engagement in BDF443 or DF457D drills during heavy use to prevent downtime. Keep a spare gearbox assembly in a workshop to enable quick repairs across compatible models.