The real gem, though, is the new exhaust brake. Like the system that debuted on the Ram Heavy Duty, when activated the system increases exhaust backpressure and uses the diesel's high compression to slow the truck down. Rather than simply turning the exhaust brake on or off, the system varies the engine braking depending on conditions to help slow the vehicle smoothly. When used with the cruise control, it can maintain the truck's speed down a grade without the driver having to step on the brakes and deactivate cruise control.
Helping to smooth out the power delivery and engine braking is the latest Allison 1000 six-speed automatic transmission. Allison has gone through the box and wrung out every last bit of mechanical efficiency, all while beefing it up to handle the extra torque of the upgraded diesel motor. The transmission controller, meanwhile, has been reprogrammed to work with the exhaust brake to keep braking as smooth and controlled as possible.
Other features include a class-leading 250 lb-ft of torque available to the PTO, a Tow/Haul mode for better control and transmission safety, a cab warm-up feature that can increase the load on the engine on cold mornings to get the heater warmed up faster and manual shifting control. Those sticking with gasoline will get an upgraded 6L90 six-speed automatic transmission, an upgrade from the 6L80 found on current models.
The end result, which can be combined with an upgraded transfer case on 4WD models, is a beefy diesel drivetrain that can handle a claimed class-leading maximum tow rating of 20,000 lbs for fifth-wheels and 16,000 lbs for a ball hitch, along with a claimed class-leading payload capacity of 6,335 lbs. In other words, more than enough to blow the Ram HD and the Ford F-Series Super Duty out of the water (though specs on the 2011 Super Duty haven't been announced yet). Not enough? Gross Vehicle Weight Rating increases to 13,000 lbs while Front Axle Weight Rating jumps to 6,000 lbs.