Ordered and installed a drive coupling from you. Put all back together and when I turned the on button and a speed button, blender would stay on for 5 seconds, then shut off and all the red lights by each speed would begin blinking off and on. When installing the rubber coupling, I had to clamp the shaft on bottom of motor and a plastic, magetic cap came off. Your parts dept. did not have this part number. How do I get my blender to stay on? Thank you.