I have only heard my newer (2-month old) Bryant 116B do this twice. And it only seems to do it when it is cool outside like I describe below.
Last night it was about 65F outside, the temperature had dropped pretty rapidly outside. But, my air kicked on because it was still warm in the house and I had the windows closed. The condenser is right next to the outside wall of our bedroom. When it shut off, it made a loud sound that sounded the a cross between a click and a clunk that I could hear inside the house.
I have only heard it happen twice (different days) both times it was relatively cool outside (cooler outside that inside the house) Is that normal?
I have no complaints with system performance, otherwise.