Can't Remove Coupling from Top of Base of Thomas TH-740-V Blender

Hi Folks,

I have a Thomas TH-740-V Blender.

When I engage the Blender Jar, the LCD and Control systems are activated but the Start/Cancel button is not activating the motor.

I need to inspect the Blender Jar Engagement Safety Sensor Switch whose location can been seen in the following image.

In order to inspect the switch, I need to be able to remove the motor but in order to remove that I need to remove the Motor Coupling at the Top of the Base as seen in the next image.

So, the question is how can I remove the Coupling?

Thanks!!