Garage Door Opener Trolley Assembly – Models 41B38691 and 41B38693 Upgrade or restore the smooth operation of your garage door opener with this complete trolley assembly. Designed for lasting performance, it offers a precise fit for a wide range of LiftMaster and Chamberlain belt drive units manufactured from 1984 to the present. Key Features and Benefits: Complete replacement assembly ensures reliable door travel and proper engagement with the drive belt Compatible with LiftMaster and Chamberlain brand garage door openers, providing an exact OEM fit Restores proper function to worn or damaged trolley components, preventing erratic door movement or failure to open/close Durably constructed for longterm use under regular daily operation Easy installation with standard tools, reducing downtime and maintenance costs Compatible Models: fit for LiftMaster and Chamberlain belt drive garage door openers, including 1270, 1280, 1280R, 2280, 2580, 2500, 2500B, 2500D, 2585, 8100, 8100M, 8200, 9200, WD822K, WD922K, WD912K, WD912KS, WD822KS. Please note that not all compatible models may be listed here. Replacement Part Numbers: 041B38693A, 41B38691, 41B38693, 41B3869, 41B38693A Typical Use Scenarios: 1. Restoring a garage door opener that has difficulty opening or closing due to a worn or broken trolley. 2. Preventive replacement during routine maintenance to extend the life of your opener system. 3. Upgrading an older LiftMaster or Chamberlain unit with hardware to improve reliability and performance. This trolley assembly is a direct replacement for the specified models and part numbers, making it the ideal choice for homeowners or technicians seeking a dependable solution to keep garage doors operating smoothly.