My coupler was split in two, and I couldn't screw it off. I had to do the following:
1. Take the blender apart (mine had 2 screws on the bottom). 2. Remove the motor housing from the blender (mine was loose from removing the two screws earlier). 3. Remove the fan by removing the fan nut. 4. Take apart the motor housing. Mine had two machine screws with 1/4" hex heads holding a bracket that tied the two ends together. Once those two screws are removed, you can take the motor out of the housing. Be careful on the fan end of the motor, because it's got two spring loaded brushes that will come together once the motor is pulled through. 6. Once you have the motor out of the housing, you'll have something to grab onto so you'll be able to unscrew the broken coupler. I used a pair of channel locks and gently grasped the motor body, and then just used a regular pair of pliers to grab the broken coupler. It's regular thread (lefty lucy righty tighty), so twist accordingly.
Once you have the coupler off, just put everything back together. The hardest part is holding apart the spring loaded brushes while you push the fan end of the motor shaft back through the motor housing.
Took me about 20 minutes to do everything.
Good luck.

If you take the fan nut off, you will see the shaft has a flat. You can use a crescent wrench on that end (not too tight or you'll damage the threads) and a visegrip on the coupler in order to get it off.

Ok, guys. I tried this before my husband got home. I had it taken apart but I dropped the motor and the threads on the shaft got bunged up. How do I go about fixing that? Neighbor said tap & die?
Thanks, Terri
terafferty at yahoo dot com

I just replaced my rubber coupling / drive shaft. I had trouble getting inside my beehive blender. The trick was 1/4 socket screws inside of the feet of the base. Once those screws and feet are off, the cover came off of the bottom, exposing the motor.

The rubber coupling unscrews from the motor. If you still have something to grip on the coupling, you can do this with the motor in place. Just hold on to the metal fan blades on the bottom (or the nut in the middle of the fan) and the coupling on the top and unscrew. If you can't grip the coupling from the outside because it broke off, you may have to take out the motor to reach it. I expect it's possible, though, everything seemed to be put together with 1/4" nuts or philips screws.