Hi there. My case might be a little too specific and unrelated to the issue/request here. I've got a 2013 3170 and after first trip heard creaking under driver side area, especially when "leaning in" to the driver side when in motion. I took it to a specialty ford truck repair shop (since dealer said it must be chassis related).
The ford repair found the bigfoot jack on the driver side was mounted just slightly touching the frame and it was causing the creaking. He said it needed to be handled by the dealer - brought to dealer, they adjusted and it was fine.
Again, may not be related to what you're seeing but in the event it happens to someone else, thought worth sharing.