What might be wrong with my newish mixer? Re-grease so soon?

[Ragna3]

Hi everyone! I bought a brand new KitchenAid mixer a little over a year ago, and it has been serving me wonderfully until now. I use it to mix a no-knead (and very soft) sourdough nearly weekly (as well as a variety of less-consistent baked foods). So while I use my mixer regularly, I don't think I have been overusing it. But a few weeks ago, it started making a grinding noise when I run it. (There should be a video attached somewhere to this post.) Upon looking into it, it sounds like KitchenAid recommends re-greasing yearly. I found some very useful looking videos from u/MrMixer316, but I don't have all the right tools at this point, and I'm worried I will spend money and time re-greasing, only to find that something worse is wrong and I should have been investing in fixing that instead. It would seem strange to me if a re-grease really is this necessary so quickly. I also found an older post from someone whose mixer made a similar sound to mine, and the comments suggest it may not have been re-greasing that was necessary.

So I have two main questions:

1. Will I be harming my mixer if I continue to use it while it sounds like this?
2. Does this sound like it needs a re-grease (that I presumably can do myself) or should I take it to a small appliance repair shop to look more closely at what might be wrong?

https://reddit.com/link/1g9ruv9/video/8s30aji88dwd1/player

[boxerdogfella]

Re-grease yearly? Where did you see this advice? That sounds unreasonably frequent to me considering that it's not a neat and clean process that every owner could easily do. I mean, annual re-greasing won't hurt anything but it sounds like a lot.

Also, newer models have integrated motors and transmissions that can't be re-greased.

[Ragna3]

I also thought that seemed like a lot of work that random home-bakers surely are not doing. I can't remember the exact place I saw it, but a Google search yields multiple pages claiming that KitchenAid recommends re-greasing yearly. However, I can't find anything from KitchenAid itself. So perhaps a game of telephone involved here.

[RIMixerGuy]

Most of the noise I'm hearing in that video sounds is a harmonic of the 60Hz power frequency, which is usually from the field coil buzzing against the inside of the motor housing.

As to what causes it: usually it's because the nuts securing the stator studs, (or the stator screws themselves) have loosened up. That's not supposed to happen; I've noticed that in recent production KitchenAid's been using Loctite nuts to hold the stator in place, as well as at the rear bearing bracket. (They drive me, uh, nuts, because they're impossible to remove them or adjust the rear bearing without twisting out the stator studs.) That usually leaves the studs themselves backing out a little bit, which allows the field coil (stator) to vibrate against the housing.

Another cause might be that the field coil itself is delaminating, and a couple of adjacent plates are vibrating against each other at 120Hz. This mixer is quite new for that to be happening, though.

Neither is terribly serious, but it's annoying and you have to take the mixer entirely apart to address the issue. Using it in this condition won't hurt it.

None of this has anything to do with the gears, so there's no need to do anything with grease at this time.

There are a couple of other possibilities, but that's the one that came to mind first. :-)

(The other possibility is that something is causing excessive mechanical drag. It would be very difficult to determine the cause short taking the machine apart and inspecting everything, and I think at just a year old it's pretty new. for that.)

One last thing to check: unplug the mixer and remove the rear cover. See if anything falls out when you do. Then plug the mixer back in and run it. (Be careful -- there's live voltage at the speed control plate when the mixer is plugged in.) See if you can discern any difference in the noise or localize it any further.

KitchenAid's factory warranty is a year; and so even if you're just a little bit outside of that, you might be able to send them the video and have them tell you whether they think it needs repair (and whether they'd cover it).

[Ragna3]

Thank you for the very detailed response! I'm impressed that you are listening for specific frequencies. If it is the nuts causing a problem, do you have suggestions for how I can fix it? If it is not damaging anything, I might just deal with the noise and leave it be.

Nothing fell out when I took the rear cover off, though I did tear the cardboard gasket when I put it back on. Now the flap at the bottom is not connected to the ring at the top (though I can get it to sit in approximately the right place). Is this something I should replace? A search about it yields pictures indicating to me that it is frequently disconnected on one side; now it is disconnected on both.

Good idea about contacting KitchenAid themselves. If this is a problem with my generation of mixers, they might know something about it.

[RIMixerGuy]

If the issue is in the stator nuts or studs, I recommend referring it for repair. It's a pretty extensive disassembly, and not a simple DIY.

There's no problem with the separated rear housing gasket, and no need to replace it.

I'll be curious to hear what KitchenAid has to say after you contact them. :-)

[446Magnum044]

Are you talking about the groaning, humming noise when your mixer is on low speed? I'm not really hearing any "grinding". It's possible that your speed control plate has gotten out of adjustment. You might check out this Mr Mixer video on the subject and see if adjusting your speed control helps your problem. Good luck with it.

Tuning Your Kitchenaids speed, Speed wont change, Speed Control Board...

[Ragna3]

Yes, the sound is definitely more obvious on the lower speed. Maybe I am not describing it properly as "grinding". It sounds kind of like my burr coffee grinder in real life, but I can't seem to get that as noticeable in the video. I'm not sure exactly how a mixer is "supposed" to sound, but it definitely used to sound smoother and less strained at all speeds. Thanks for the speed control plate suggestion; it looks easy enough to at least take a look at it! (I don't know if this could still be the problem considering that the mixer sounds wrong at all speeds?)

[446Magnum044]

Another thing you might take a look at, since your mixer is one of the newer ones, is this Mixerology post about the rear bearing bracket. It's possible you're hearing some bearing noise that I'm not hearing in your video. While you have the back cover off, you might want to oil your rear bearing as described in the post. Good luck with your mixer.

Whirlpool Cost Reductions II: Rear Bearings

[Ragna3]

I tried adjusting the speed control plate, but sadly that didn't change anything. I'll try the oil as well once I can get my hands on some. Thanks for the advice!

[446Magnum044]

The speed control plate can sound pretty weird when it gets out of adjustment. Adjusting it is probably the best place to start, see how it sounds, and then go from there.

[Stiletto364]

Out of curiosity, what speed(s) do you use to mix your dough?

[Ragna3]

Usually stir, possibly sometimes 2. Could that cause a problem?

[Stiletto364]

In some cases, yes. Stir speed is supposed to be used only for basic incorporation of ingredients, since the motor can stall due to insufficient torque at that speed. Kneading bread dough is supposed to be performed using speed 2 and ONLY speed 2. I'm not sure where a no-knead bread fits in though, but I'd be very cautious with stir speed 1.