Sorry guys. My first blog and pretty sure I am in the wrong area. I have a pair of Trane XR 15's we installed new in June of 2010. Ever since we have had a loud clunk at shutdown. It wakes both us and our neighbors up early, and does not stop. Every 45mins to an hour all day. Sadly, a friend of mine is the local Trane dealer and despite more than a dozen calls to our home and new parts, etc. we have no solution and now are at odds with each other. Any ideas???