Our 560 certainly whistles as it drives down the road. Cary said that other customers have noticed this as well. We put a piece of plastic rope in the curved rope track at the front top of the trailer and that fixed it!
Nice one. The ends of that awning rail above the window are like little organ pipes on a 560. I have never heard it for some reason but many have pointed it out to me including Craig. Apparently I have poor hearing in the upper ranges.
So believe it or not our trailer whistled from the get go....
As we followed Craig to the state line to take delivery we could hear the whistle. We had no idea what it was until he stopped to buy some foam insluation he could stuff into the rail channel. We returned to following and the pesky sound was gone.