KitchenAid Just Doesn’t Give a Damn

If you own a pre-2006 KitchenAid Professional 600, be aware that it will probably come to a grinding, screeching halt if you make a lot of bread. When it crashes you will be assaulted by one of the most painful and soul-crushing sounds you are likely to hear in a kitchen. Your beautiful mixer is dead. What is worse, KitchenAid just doesn’t give a damn.

My Professional 600 was a gift from my wife, who thought she was buying her bread-crazy husband the biggest, baddest mixer on the block. It is certainly marketed that way.

The overachiever of the stand mixer family, it has a Flour Power rating of 14 cups. That means it can mix enough dough for 8 loaves of bread or 13 dozen cookies in a single bowl … Powerfully churns through yeast bread dough and triple batches of cookie dough.

So why did my 8-cup soft sandwich bread recipe kill it? As it turns out, the Professional 600 mixers made before August of 2006 have a plastic gear housing that is completely inadequate for the size of the motor. Put a strain on the mixing head — bread dough, for instance — and the housing flexes, throwing the whole gear train out of alignment. When that happens the gears strip, locking up the whole assembly and causing an ear splitting shriek that will be etched in your memory forever. It is a horrible sound. Kitchenaid redesigned the gear housing in 2006, replacing it with a metal housing capable of taking the load put out by the motor. They repaired the Professional 600s that died under warranty but didn’t put out a service bulletin or recall notice for the others. We were left on our own. You see, the mixer doesn’t self destruct the first time you use it, the problem is cumulative. The flex gets worse with time until one day the gearbox flexes just far enough to cause a train wreck. It happened often enough that the KitchenAid engineers built a new gearbox. They just didn’t tell the rest of us. It took an engineer with a dead mixer to find out why the gears stripped the way they did.

My mixer is out of warranty so I wanted to see what my options were. I did a little research and found dozens of other Professional 600 owners who experienced exactly the same symptoms and mixer death. One of them was an engineer who took his mixer apart. It was he who discovered why the gears stripped the way they did. There was a detailed analysis with photos on his website, but it is no longer available.  Given that this was a known design flaw — one that KitchenAid admitted when redesigning the gearbox — I asked them to cover the repair of my mixer. They refused, charging me $150 to replace the gears and gearbox housing. Their condescending customer service representative claimed A) that mixing 8 cups of flour for seven minutes, rather than the recommended five, was responsible for the lockup that killed the mixer, and B) that while the gearbox did indeed crack, the gears stripped first, so the gearbox couldn’t have been the problem. I pointed out that the gearbox flexes, causing the gears to strip before the housing cracks but she didn’t want to hear it. The problem was obviously my fault, and her tone suggested that I was probably lying about only mixing 8 cups of flour. It was an infuriating conversation. In short, Kitchenaid markets the Professional 600 as a heavy duty mixer designed to knead bread dough knowing that 90% of their customers are going to be making cakes, cookies and meringues, which put no strain on the motor. It’s the 10% of us who do bake bread (or use the meat grinder) on a regular basis who are screwed because KitchenAid won’t stand behind its products.

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  1. I’m glad I read all the reviews and so disappointed in Kitchen Aid. It’s such a good looking piece of equipment.
    I bought a silver one this afternoon at Costco and I’m going to box it up and return it tomorrow. I can’t
    stand the thought of it dying and waiting to see when it’s going to go. It costs too much for just it’s looks.

  2. Just picked up a broken KA professional HD off of Craigslist. Opened it up and it had a cracked plastic gear housing and stripped worm gear and follower gear. Looking closely at the design of the base of the gear housing, I think the problem is not with the gears, but with how the front and rear bearings on the worm gear are set in the base housing. The bearings have flat edges that are supposed to be placed vertically into the housing to hold the gear in place and prevent the bearings from spinning. However, the housing base does not have flat sides to accomodate the bearings, allowing them to spin in the housing. This results in play in the worm gear so that it is not tightly meshed with the follower gear. Initially, there is substantial “teeth” in the gear to accommodate the play in the gears, but over time and under load this creates wear in one or both of the gears, resulting in eventual failure. The bearings fit tight in the plastic housing (although it also does not have flat sides in the bearing groove), so this transfers all the torque to the housing, which eventually cracks along the length of the housing by the worm gear (or at the mounting screw holes). This is clearly a design failure by KA, along with using a plastic housing. The only solution would be to redesign the base of the gear housing to properly hold the bearings in place.

  3. The design of gear train is so stupid. Mine had a plastic gear housing which cracked after kneading 5 cups of flour dough a few times. I am an engineer. I replaced it with the redesigned metal housing. In my humble opinion, the design of the replacement is poor as there is too much play throughout the gear transmission. It will not sustain the heavy load of kneading bread dough. Most high school kids could do better design than this.

  4. My KA professional HD stand mixer lower metal gear box cracked. the vertical shaft holder dropped out.

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