How to troubleshoot & fix a rattling or grinding garbage disposal

A rattling or grinding noise coming from your garbage disposal can be annoying and sometimes concerning. The good news is that most of these issues can be fixed with a little troubleshooting and some basic DIY know-how. We’ll walk through the common causes of these noises and how to fix them yourself. 

Note: The information provided in this article may not apply to your specific appliance model. While we strive to offer helpful advice for DIY appliance repairs, variations in models and configurations can lead to differences in troubleshooting steps, error codes, and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model.

Safety precautions

When working on any appliance, remember to keep safety first. Here are some tips to keep in mind: 

• Always power off and unplug your appliance or switch off the circuit breaker before attempting any maintenance or replacement work. This keeps you safe by preventing any risk of injury from electric shock.
• Wear insulated work gloves to protect your hands from sharp metal parts, pinching hazards and debris.
• Take your time and don’t rush while working to prevent accidents and personal injuries.
• Work in a well-lit area so you can clearly see and access the interior parts.
• Clear your workspace of clutter and other obstacles. Keep children and pets away from the work area.
• Never work on internal parts with bare wet hands. Make sure the work area is completely dry.
• Check your user manual to see if there are specific installation or safety instructions for your part or appliance. 
• Be gentle when handling or removing parts. Excessive force might damage the appliance or cause injury.
• Wear safety glasses when working with chemicals, dust or cleaning large debris to prevent injury. 
• If the appliance has recently been used, give it plenty of time for any heating parts to cool down before working on it. 
• Take pictures or make a note of wiring terminals or other connections before disconnecting to prevent any problems with reassembly.
• When working with wires, avoid touching any exposed wires or terminals. If you need to touch a wire, use a non-conductive tool or wear insulating gloves to prevent electrical shock.

Read more: How to prep your garbage disposal for Thanksgiving and other holiday events

Cause 1: Foreign objects stuck in the disposal

Sometimes, items like utensils, bones, or other non-food materials can accidentally fall into the garbage disposal. When the blades spin, these objects can cause a rattling or grinding noise as they bounce around inside.

How to fix it:

1. Unplug the garbage disposal from the outlet under the sink, or turn off the circuit breaker to cut the power supply.
2. Shine a flashlight into the disposal through the sink opening to locate the foreign object.
3. Look for anything metallic, hard, or out of place that could be causing the noise.
4. Use tongs or pliers to carefully extract the object. Never put your hands inside the disposal, even if it’s turned off.
5. Restore power by plugging the unit back in or switching the breaker on.
6. Run cold water and turn on the disposal to check if the noise is gone.

Read more: How To Quickly And Easily Unclog Your Kitchen Double Sink With A Garbage Disposal

Cause 2: Loose or damaged impellers

The impellers inside your garbage disposal are responsible for pushing food waste against the grinding ring. Over time, they can loosen, become misaligned, or even wear down, causing them to rattle or grind unevenly during operation.

How to fix it:

1. Unplug the disposal or turn off the circuit breaker to ensure it’s completely powered down.
2. Use a flashlight to look inside the disposal.
3. Check for visible damage, misalignment, or signs of wear on the impellers.
4. Insert an Allen wrench into the hex-shaped hole on the bottom of the disposal.
5. Turn the wrench back and forth to rotate the flywheel manually.
6. Observe if the impellers move freely or if they seem loose or stuck.
7. If the impellers are visibly loose or damaged, refer to your disposal manual to determine if they are replaceable.
8. Restore power and run the disposal with cold water to check if the noise is resolved.

If the impellers are damaged beyond repair or the disposal doesn’t have replaceable parts, it might be time to consider replacing the entire unit.

Cause 3: Worn-out grinding ring

The grinding ring is a serrated metal component that helps break down food waste into small particles. Over time, this ring can wear down, become dull, or even crack, leading to unusual grinding noises and reduced performance.

How to fix it:

1. Unplug the disposal or switch off the circuit breaker to ensure safety.
2. Use a flashlight to look inside the disposal.
3. Check the grinding ring for visible signs of wear, cracks, or dullness.
4. Insert an Allen wrench into the hex hole at the bottom of the unit and rotate the flywheel manually.
5. Observe whether the grinding ring appears to be grinding food waste effectively or if it looks worn out.
6. Consult your disposal manual to see if the grinding ring can be replaced.
7. If it is replaceable, order the correct part for your model and follow the instructions to swap it out.
8. Restore power and test the disposal with water and soft food scraps to see if the grinding noise is gone.

If the grinding ring is not replaceable or the disposal’s overall performance has declined significantly, replacing the entire unit might be the most practical solution.

Cause 4: Loose mounting assembly

The mounting assembly holds the garbage disposal securely to the sink. Over time, the screws or brackets in the mounting assembly can loosen due to vibrations during regular use. This can cause the disposal to rattle or make grinding noises as it moves slightly out of place.

How to fix it:

1. Unplug the disposal or switch off the circuit breaker to ensure safety.
2. Look underneath the sink at the connection between the disposal and the sink flange.
3. Check for loose screws, brackets, or other fasteners in the mounting assembly.
4. Use a screwdriver or wrench to tighten any loose screws or brackets.
5. If the mounting assembly uses a locking ring, ensure it is securely rotated into place.
6. Verify that the disposal is sitting level and securely attached to the sink.
7. Adjust the unit if necessary to ensure stability.
8. Restore power and run the disposal with cold water to see if the noise is resolved.

Cause 5: Debris buildup in the grinding chamber

Over time, grease, food particles, and other debris can accumulate inside the grinding chamber. This buildup can cause uneven grinding, leading to rattling or grinding noises during operation.

How to fix it:

1. Unplug the disposal or switch off the circuit breaker before cleaning.
2. Shine a flashlight into the disposal to look for visible debris, grease, or hardened residue inside the grinding chamber.
3. Pour half a cup of baking soda into the disposal, followed by half a cup of vinegar.
4. Let the mixture fizz and break down buildup for about 10–15 minutes.
5. Rinse the chamber with hot water while running the disposal.
6. Run cold water and test the disposal to see if the noise has been resolved.

Use ice and rock salt for deeper cleaning:

1. Fill the disposal with a few ice cubes and a tablespoon of rock salt.
2. Turn on the disposal while running cold water. The ice and salt will help scrub the chamber and clean off any remaining residue.

Cause 6: Motor issues

If the motor in your garbage disposal is struggling, it can produce grinding or rattling noises as it attempts to power the flywheel and grinding components. This may be due to age, wear, or internal damage.

How to fix it:

1. Unplug the disposal or switch off the circuit breaker to ensure safety.
2. Insert an Allen wrench into the hex-shaped hole at the bottom of the disposal.
3. Rotate the flywheel back and forth to ensure it spins freely.
4. If the flywheel is stiff or stuck, there may be an internal jam or motor issue.
5. Plug the disposal back in and turn on the switch to listen for any motor sounds.
6. If the motor hums but the blades don’t spin, it could indicate the motor is failing or there is a blockage.

Test the motor with a multimeter:

1. Disconnect power to the unit.
2. Remove the disposal from under the sink and access the motor terminals.
3. Use a multimeter to check for continuity at the motor terminals.
4. If the motor shows no continuity, it is likely burned out and will need replacement.

If the motor is failing and cannot be repaired, replacing the entire garbage disposal is often the most practical solution.

Read more: How to fix a burning smell in your garbage disposal

We’ve got your back

Dealing with a noisy garbage disposal isn’t fun, but with these pointers, you’re set to fix it up. Remember, taking care of your disposal not only silences those unwanted sounds but also helps it last longer.

If you need replacement parts or want more in-depth repair guides, head over to AppliancePartsPros.com. We’re here to help you keep your appliances in tip-top shape.

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Got questions or need a hand? Don’t hesitate to reach out. Our team’s always ready to help you on your DIY repair journey.