Dont buy a deisel , currently there is NO good eisel motors out there to buy unless you go pre 07 . Duramax id stay away from , allison trans is a watered down allison , nothing like you think of in a medium duty truck . I do towing for a living , seems duramax is hit and miss , one guy has no issue the next guy nothing but issues . Ford , well prior to the 6.0L they had a good diesel truck , 6.0 has been bad news the newer 6.4 is it ? not any better . All are having issues sorting out these new filttration systems they had to put on . Urea burners now . Id go to a GM 8.1 L if your towing or a Ford V10 Starting in 2012 Ford is putting the v 10 back into the F 650 models even due to sales on the diesel motor . Do some math regarding gas v's diesel power . Giving the cost difference at purchase , oil change and fuel cost theres no value in a diesel pickup .