At just over 1,000 miles and one month of ownership, my EPB has a single, moderately loud "clunking" sound at the very end of the engagement travel. The sound seems to be emanating from the rear of the car. Disengagement is noiseless except for the motor sound. The EPB seems to function normally and holds the car well by itself on moderately steep slopes. The EPB light on the display operates as expected. I had my car in to the dealer yesterday and they did an alignment procedure on the EPB that was supplied to them by GM Tech Support. When I picked up my Volt, the "clunking" sound was gone and continued to be gone for the rest of the day and evening. This morning the "clunking" sound is back. My dealer is contacting GM again for more info. Has anyone had this issue and, if so, what was the resolution? Thanks in advance for any words of wisdom.