this is a very common problem with longer Class C or B+'s due to the distance between the rear axles and the rear of the coach. this problem is often referred to as "tail wag". We experienced the same problem when we bought our 2012 29' B+. Roadmaster figured out part of the problem which was the need for a rear sway bar and a trac bar. that fixed most of the problem, but not all. I then had a front end alignment and that fixed it all. Ford probably aligns the front end when the ship the unit to the RV company, but by the time the RV company is done with their work, everything changes and that is why an alignment is needed again. My RV company (Monaco)paid for the alignment even though the warranty had expired. Do a search on this or other sites and you will see a lot of comments as this is very common. Good luck.