LiftMaster MJ5011 Replacement Parts — Medium-Duty Logic Jackshaft Operator

Genuine LiftMaster replacement parts for the MJ medium-duty logic jackshaft operator. The MJ5011 is the standard version — 1/2 HP, 120V, single phase. Use the exploded diagram to identify your part by its key number, then match it to the tables below. Click any part number to go straight to that item.

The MJ is built in right-hand and left-hand versions and the frames are not interchangeable, so check which side your operator mounts on before ordering frame parts. A letter after the model number tells you the rest — R or L is the hand, U or E is the logic board type. Both are on the operator’s data label. The MJ also has a floor-level disconnect assembly that the MT and BMT do not; those parts are the D group below.

Models Covered

MJ5011 (1/2 HP, 120V, 1PH — most common), MJ5025 (230V) — also sold as MJ5011U, MJ5011R and MJ5011L

Replacement Parts

Service Kits

The motor’s part number is printed on the motor’s own data label. If you can reach it, read the number straight off the label and match it above — that is the most reliable way to order the right motor.

Electrical box parts. The MJ was built with the shared medium-duty logic control box and, on earlier mechanical units, the medium-duty mechanical box. Both are the same enclosures fitted to the MT, BMT and MH.

Electrical Box — Logic Control

Electrical Box — Mechanical Operators