Diagnosis
The loud grinding or rhythmic clicking noise emanating from the right side of the Brother MFC-L2820DW is almost always caused by a mechanical failure in the main drive gear assembly or the paper feed drive train. Specifically, the nylon teeth on the primary drive gear (Part #LJ4514001) often shear off or wear down, causing the gear to slip. When the printer attempts to engage the paper feed or the drum rotation, the misaligned teeth clash, creating a high-pitched grinding sound. You can confirm this by opening the front cover and removing the toner cartridge and drum unit. If the noise persists while the printer is attempting to "initialize" or start a print job without paper, the issue is localized to the drive gears. If the noise only occurs when paper is physically being pulled, the problem may lie with the pickup roller assembly or a foreign object (like a staple or paperclip) lodged in the right-side gear train, causing the gears to jump tracks.
How to Fix It
Replacing the drive gear assembly requires a full teardown of the right-side chassis. Ensure the printer is unplugged and completely cooled down before starting.
- Remove the toner and drum assembly. Open the rear access door and remove any remaining jammed paper scraps using tweezers.
- Remove the side panels by unscrewing the chassis screws (typically Phillips #2). Carefully lift the right-side plastic housing to expose the gear train.
- Locate the main drive gear assembly. Inspect the teeth for any visible gaps or plastic shavings.
- Use a gear puller or a small flat-head screwdriver to gently pry the worn gear (LJ4514001) off its drive shaft. Be careful not to bend the metal shaft, as this will cause permanent misalignment.
- Clean the shaft with a lint-free cloth and a small amount of isopropyl alcohol to remove old, degraded grease.
- Slide the new gear assembly onto the shaft, ensuring it clicks fully into place. It must be flush against the drive motor housing to avoid slippage.
- Apply a small amount of high-temperature synthetic white lithium grease to the gear teeth. Do not over-lubricate, as excess grease attracts paper dust and creates a grinding paste.
- Reassemble the side panels and test the printer with a single-page print job.
If That Didn't Work
- Inspect the Fuser Drive Gear. If the main gear is new but the clicking persists, the gear on the right side of the fuser unit may have stripped. Remove the fuser assembly and check the drive gear for missing teeth; if damaged, the entire fuser unit typically needs replacement as the gears are integrated.
- Check for "Paper Path Obstructions." A tiny piece of torn paper lodged in the right-side gear housing can act as a wedge, forcing the gears to skip. Use a flashlight to inspect the gaps between the gears for any debris and clear it with compressed air.
- Verify the Pickup Roller Tension. If the noise sounds more like a "thump-click," the pickup roller shaft may be slipping. Remove the pickup roller, clean the shaft with alcohol, and ensure the spring tensioner is seated correctly in its notch.
- Test the Drum Unit Drive. Occasionally, the gear on the drum unit itself (not the printer) fails. Insert a known-working drum unit to see if the noise disappears; if it does, the drum unit's internal gear train is the culprit.
Heads Up
- Avoid using WD-40 or petroleum-based lubricants on the gears; these will dissolve the nylon plastic over time, leading to total gear failure. Only use synthetic lithium grease.
- Always run a "Cleaning Page" or print 5-10 blank pages after replacing gears to ensure the lubricant is evenly distributed across the gear train.
- Check your page count in the settings; if you are approaching 10,000 pages, consider replacing the pickup rollers proactively to reduce the torque load on the drive gears.
- When reassembling the chassis, do not over-tighten the side panel screws, as this can warp the plastic frame and put uneven pressure on the gear shafts, causing a new clicking sound.