I have a 2014 6.7 AT mega cab and it came factory with a 1pc shaft. Megas and long box crew have the same wheelbase. Part # is 68241637AA list is $560 so if you can get 25% off or so it makes it a very reasonable price and you get new joints and slip yoke. If you look up a shaft for a 2008 model year its a lot more $ like $900