





The LiftMaster 041B3869-3A Belt Drive Trolley Kit is a genuine replacement trolley assembly designed for use with select LiftMaster and Chamberlain belt drive garage door openers. The trolley connects the opener carriage to the garage door arm, allowing the motor to open and close the door smoothly along the rail.
This replacement kit is used when the original trolley becomes worn, damaged, or fails to properly engage the belt drive system. Installing a new trolley helps restore proper door movement and reliable opener operation.
Always verify your garage door opener model and replacement parts diagram before ordering to ensure compatibility.
Compatible with LiftMaster garage door opener models including: 8155WMC, 8355, 8355-267, 8355W, 84501MC, 84504RMC, 8550WLB, and 87504R-267MC.
Disconnect power to the garage door opener before performing service or replacing internal components. Refer to the opener installation manual or replacement parts diagram to confirm correct part compatibility prior to installation.


We've found that replacing the majority of the hinges and installing the rest of the kit does a pretty good job of silencing the door without needing to deal with that bottom roller. If you really feel it needs to be changed, we have a separate process for that, but it's not necessary for most installations.
