The LiftMaster 41B3869-3A Belt Drive Trolley Assembly is a genuine replacement trolley for select LiftMaster and Chamberlain belt-drive garage door openers. This component rides along the opener’s rail to move the door, engaging the belt and connecting to the garage door arm for smooth open/close operation. It is commonly used to restore functionality when a worn or broken trolley causes slipping, irregular travel, or failure to engage the door. Installation typically involves disconnecting power, relieving belt tension, sliding off the old trolley, and installing the new assembly per the opener’s service manual, then re-tensioning the belt and testing safety reversal systems.
This OEM trolley assembly is designed for compatibility with specific LiftMaster/Chamberlain belt-drive models that use the 41B3869-3A part number on their parts lists. Because compatibility varies by model and production year, buyers should verify fit by checking the opener’s model number and parts diagram or consulting LiftMaster support resources. The trolley is intended for residential belt-drive applications and works with standard LiftMaster safety systems and travel limits programmed at the head unit; no separate programming is required for the trolley itself beyond normal opener setup and limit adjustments after installation. For safe operation, always disconnect power before servicing, ensure proper belt tension and travel limits, and test the photo eyes and auto-reverse after replacement.
Compatible with Chamberlain, Craftsman and LiftMaster belt drive models that use a "T" rail.