KitchenAid Mixer Worm Gear Issues? Here’s How to Fix It

Is your KitchenAid stand mixer struggling to mix properly? A worn-out worm gear might be the culprit. This small but essential part keeps the mixing action running smoothly, and over time, it can wear down, leading to noise or performance issues. Instead of replacing the entire mixer, you can swap out the worm gear yourself with a few basic tools.

Signs Your Worm Gear Needs Replacement

A faulty worm gear can cause several issues in your mixer. Watch out for these signs before deciding to replace it:

• Unusual noises: Grinding, clicking, or loud whirring sounds may indicate gear damage.
• Mixing problems: If the mixer struggles to rotate the beaters or stops altogether, the worm gear could be worn down.
• Slipping or skipping motion: If the beaters hesitate or move inconsistently, it may be time for a new gear.
• Burning smell: A damaged gear can strain the motor, sometimes leading to overheating and a burnt smell.
• Visible wear: If you’ve opened the mixer and see stripped or damaged gear teeth, replacement is necessary.

Tools You’ll Need

• Phillips screwdriver
• Small flathead screwdriver
• Snap ring pliers
• Punch
• Planetary gear grease
• Replacement worm gear WP9709231 (compatible with your mixer model)

Safety Tips

Before starting, follow these precautions to avoid injuries or damage to your mixer:

• Unplug the mixer or turn off the circuit breaker before working on it.
• If the mixer was recently in use, allow it to cool down to prevent burns.
• Avoid touching exposed wires or terminals. If necessary, use a non-conductive tool or wear insulated gloves.
• Take your time—rushing can lead to accidents.
• Work in a well-lit area to clearly see the parts you’re handling.
• Keep the workspace clear of clutter, and make sure children and pets are not nearby.
• Dry your hands and work area before handling any electrical components.
• Refer to your user manual for any model-specific instructions.
• Handle parts carefully—forcing components can cause damage.
• Wear safety glasses if working with grease, dust, or debris.

How to Replace the Worm Gear in a KitchenAid Mixer

Here are the steps to disassemble your mixer, replace the worm gear, and put everything back together for smooth operation.

Step 1. Prepare the Mixer

1. Unplug the mixer.
2. Lower the bowl to the lowest position.
3. Remove the beater by lifting it slightly, rotating it clockwise until it drops down, then pulling it out.
4. Lift the bowl off the mounting pegs and set it aside.

Step 2. Remove the Mixer Cover

5. Locate the screw at the back of the mixer that holds the trim in place.
6. Use a Phillips screwdriver to remove the screw and slide off the trim band.
7. Find the four screws (two on each side) that secure the cover.
8. Use a Phillips screwdriver to remove all four screws and lift off the cover.

Step 3. Access the Transmission

9. Locate the two screws that hold the speed control board in place.
10. Remove the screws with a Phillips screwdriver and lift the speed control board out of the way.
11. Use a small flat-head screwdriver to release the tabs securing the sensor.
12. Press on both sides to release the tabs, then pull the sensor out of the motor.
13. Swing the speed control board aside to access the transmission.
14. Locate the four screws securing the transmission cover.
15. Use a Phillips screwdriver to remove all four screws and lift off the transmission housing.

Step 4. Remove the Old Worm Gear

16. Remove the accessory drive gear and wipe off any grease.
17. Remove the old worm gear and bearings and wipe off any grease.
18. Slide the bearings off both ends of the worm gear.
19. Clean the drive shaft and surrounding gears to remove old grease.
20. Use snap ring pliers to carefully remove the snap ring without spreading it too far.
21. Lift off the beveled gear and set it aside.
22. Use a punch tool to push out the pin securing the worm follower gear.
23. Use a flat-head screwdriver to help lift the worm follower gear off the shaft while holding onto the planetary assembly below to prevent it from falling.
24. Set the planetary assembly aside.
25. Use a clean cloth or paper towel to remove old grease from the gear case.

Step 5. Install the New Worm Gear

26. Push in the planetary shaft bearing so it is seated in the housing.
27. Lift the planetary assembly back up into place.
28. Apply new grease to the worm follower gear.
29. Set the worm follower gear onto the shaft and insert the pin to hold it in place.
30. Grease both the external gear and the pinion gear.
31. Lift the planetary assembly into place inside the mixer.
32. Apply grease to the bevel gear and set it onto the shaft.
33. Align the bevel gear so the snap ring can be reattached.
34. Attach the rear sleeve bearing, thrust bearing, and front sleeve bearing to the new worm gear.
35. Align the flats of the bearings vertically.
36. Apply grease to the new worm gear and place it inside the gear case.
37. Grease the accessory drive gear and place it back in the housing.
38. Pack extra grease around the gears but avoid overfilling the housing.

Step 6. Reassemble the Mixer

39. Place the transmission housing back onto the mixer.
40. Secure the transmission housing with the four screws.
41. Position the speed control board back in place.
42. Plug in the sensor and secure it with screws.
43. Place the mixer cover back on.
44. Secure the cover with the four screws.
45. Slide the trim ring into place.
46. Secure the trim ring with the rear screw.

47. Place the bowl onto the mounting pegs.
48. Reinstall the beater and lock it into place.
49. Plug the mixer back in.
50. Turn the mixer on to check for smooth operation.

Maintenance Tips to Prevent Future Gear Wear

To keep your mixer running smoothly and prevent premature gear failure, follow these maintenance tips:

• Use the right speed settings: Avoid overloading the mixer at high speeds, which can put stress on the gears.
• Keep the motor cool: Long mixing sessions can cause overheating. Let the mixer rest between uses.
• Grease the gears regularly: Periodic lubrication helps reduce friction and wear.
• Mix within the recommended capacity: Overloading the bowl can put too much strain on the gears.
• Inspect for wear: Occasionally check for signs of damage so you can replace parts before they fail completely.

Read More: 5 Simple Steps to Clean a Stand Mixer for a Streak-Free Shine

Looking Ahead

Your KitchenAid mixer works hard every time you knead dough or mix a thick batter, and over time, that worm gear takes on a lot of stress. If it wears out, swapping it for a new one is a much cheaper fix than replacing the whole mixer. Now that you know how to do it, you won’t have to worry if your mixer starts acting up.

Taking care of your mixer will help it last longer, but when things wear down, you can handle the repair yourself. A little grease, a fresh gear, and you’re back to mixing without a hitch.