 TITAN XD 5.6 Endurance gas guzzler. The XD is 1500 lbs heavier than the regular Titan, thus resulting in about 12.6 to 13 mpg around town. However without towing can achieve 16 / 17 mpg on interstate driving 75 to 78 mpg on cruise control.  Transmission is ok, however at slow acceleration  (city driving in traffic) it shifts from 2 through 4th gear too quickly dropping rpm  to near 1500 and loose so much torque it will balk. To overcome the torque lose you will instinctively press gas harder...suddenly you are in 2nd gear at 4000 r.p.m. where it has super power. Unfortunately the vehicle in front of you may not be increasing speed from 15 to 60 nearly as quickly as you!