Just recently purchased the 2008 F-350. When I am engaging the front diff it doesn't seem to engage for a long period of time and then when it engages I am getting a large thud from the front diff. It happens almost every time I engage 4X4. The 2002 that I just traded in had the Auto/Manual hubs and would only make the same thud under operator error. (Spinning tires, one off the ground, etc.) I assume that the hub operates under the same principal as the old style and don't understand the issue with the new hub. Is this a common issue? What are the differences between the old style and the new, besides the cap? MAybe the truck will go in for its first dose of warranty work...