Motor runs, beater stopped rotating. Some gear sounds heard before it stopped. Beater will not turn at any speed setting.

Make sure your Beater can slip in and out of the Beater Shaft
easily. Do not force the beater onto the Shaft if the shaft is bent.
If it cannot be removed easily by hand, use a soft rubber mallet
(not a steel hammer) to slightly tap the beater so it can be moved
up and down the shaft or from side to side. Then you can easily
turn the beater left and remove it from the shaft.

From Kitchenaid Manual:
To Attach Flat Beater, Wire Whip, or Dough Hook
1. Turn speed control to OFF.
2. Unplug stand mixer or disconnect power.
3. Tilt motor head back.
4. Slip beater onto beater shaft and press upward
as far as possible.
5. Turn beater to right, hooking beater over pin on shaft.
6. Plug into a grounded 3 prong outlet.

To Remove Flat Beater, Wire Whip or Dough Hook
1. Turn speed control to OFF.
2. Unplug stand mixer or disconnect power.
3. Tilt motor head back.
4. Press beater upward as far as possible and turn left.
5. Pull beater from beater shaft

Make sure your Beater can slip in and out of the Beater Shaft

easily. Do not force the beater onto the Shaft if the shaft is bent.

If it cannot be removed easily by hand, use a soft rubber mallet

(not a steel hammer) to slightly tap the beater so it can be moved

up and down the shaft or from side to side. Then you can easily

turn the beater left and remove it from the shaft.

From Kitchenaid Manual:

To Attach Flat Beater, Wire Whip, or Dough Hook

1. Turn speed control to OFF.

2. Unplug stand mixer or disconnect power.

3. Tilt motor head back.

4. Slip beater onto beater shaft and press upward

as far as possible.

5. Turn beater to right, hooking beater over pin on shaft.

6. Plug into a grounded 3 prong outlet.

To Remove Flat Beater, Wire Whip or Dough Hook

1. Turn speed control to OFF.

2. Unplug stand mixer or disconnect power.

3. Tilt motor head back.

4. Press beater upward as far as possible and turn left.
5. Pull beater from beater shaft.

Make sure your Beater can slip in and out of the Beater Shaft
easily. Do not force the beater onto the Shaft if the shaft is bent.
If it cannot be removed easily by hand, use a soft rubber mallet
(not a steel hammer) to slightly tap the beater so it can be moved
up and down the shaft or from side to side. Then you can easily
turn the beater left and remove it from the shaft.

From Kitchenaid Manual:
To Attach Flat Beater, Wire Whip, or Dough Hook
1. Turn speed control to OFF.
2. Unplug stand mixer or disconnect power.
3. Tilt motor head back.
4. Slip beater onto beater shaft and press upward
as far as possible.
5. Turn beater to right, hooking beater over pin on shaft.
6. Plug into a grounded 3 prong outlet.

To Remove Flat Beater, Wire Whip or Dough Hook
1. Turn speed control to OFF.
2. Unplug stand mixer or disconnect power.
3. Tilt motor head back.
4. Press beater upward as far as possible and turn left.
5. Pull beater from beater shaft

If you can hear the motor spinning and the beater does not spin, the worm gear has probably failed. These fail frequently, specially after using them beyond there designed limits. The motor heats up and the gear, which is a type of plastic or nylon, melts.

You have probably stripped a gear in the gear housing. Here is the breakdown of the gearbox:

http://shared.whirlpoolcorp.com/assets/pdfs/literature/Repair%20Part%20List%20-%208212010.pdf

The newer "more improved" mixers use plastic gears and they can't take the beating, no pun intended, and fail.

The good news is that the most likely gear to fail is cheap. Here it is on amazon.com:

http://www.amazon.com/KitchenAid-W10112253-Worm-Gear/dp/B0006HLAVA

http://www.misterfixit.com

Hi, This sounds like you have an issue with the planetary gear system. The mixer has a plastic worm gear inside the planetary that is prone to wear and failure. I would bet that it needs replaceing.

It sounds like you sheared a key in the transmission.Does any gears work?were you using 1st gear for dough?

you most likely stripped the plastic gear (Worm gear???).  This gear is designed to fail to prevent the motor from burning out under EXTREME loads (i.e. when a metal piece falls into the bowl). The plastic gear is much cheaper than a new motor.  Look around on this site to see how to get at/repair the gear.  I've found many parts on eBay.com and also PartSelect.com.

It sounds like the nylon gear is stripped out. It is a rather easy to replace and also inexpensive. A gentlemen posted a step by step site to replace the gear. The link is http://www.neilcrockett.com/mixer.htm
Good Luck

you snapped one of the drive gears. Your gonna have to get someone whos mechanicly inclined to take apart the drive motor assy and see whats broke. You should be able to get the parts at http://www.repairclinic.com good luck