MPLock Identifier
Identify your lock now!
Identify your lock now!
Multipoint Lock Gearbox
The gearbox is the central working mechanism of a multipoint lock. It is where the handle, spindle, cylinder, latch, and deadbolt all operate, and where motion is transferred to the rest of the lock.
Quick Need-to-know
- Gearbox, lock box, lock case, and main gear usually mean the same part
- It acts as the control center of the lock
- Most multipoint failures trace back to gearbox issues
- Some systems allow gearbox-only replacement, others do not
Note: If the gearbox fails, the rest of the lock usually stops functioning correctly.
Gearbox Front View
Gearbox Full Lock View
What Happens Inside the Gearbox
- Receives movement from the handle spindle
- Operates the latch and deadbolt
- Drives extensions and locking devices above and below
- Synchronizes all locking points
How to Identify the Gearbox on the Door
The gearbox sits directly behind the handle on the edge of the door. It is usually the thickest section of the lock body and contains the highest concentration of moving parts.
Signs the Gearbox May Be the Problem
- Handle lifts but locking points do not move
- Key turns but the deadbolt does not extend
- Handle feels loose or slips
- Grinding or binding during operation
Gearbox Replacement vs Full Lock Replacement
Some multipoint systems allow the gearbox to be replaced on its own. Others require replacing the entire lock assembly because the gearbox is integrated into the strip.
If you’re evaluating replacement options or want to see parts that include gearboxes and related assemblies, you can browse our gearbox results for compatible hardware.