There are more trucks than cars out here in Arizona, and they’re all working hard. The hills are so steep, there are road signs warning drivers to turn off their air conditioning so their engines don’t overheat.So I feel right at home in GM’s new heavy-duty trucks, the Chevrolet Silverado and GMC Sierra 2500 and 3500, which have been overhauled for 2015.The greasy bits are still the same: the platform, suspension and engines carry over from the HD’s makeover in 2011, although with some steering tweaks that improve the handling.The news is in the cab and cabin, which bring them in line with the all-new 1500 trucks that GM introduced for 2014.That includes a vastly improved interior, a new infotainment system and safety warning programs, beefier exterior styling, improved cooling, and the simple but brilliant integrated bumper step for bed access.The previous extended cab is replaced with a new double cab, which has front-hinged doors instead of two rear-hinged ones.As in the outgoing 2014 HD trucks (and how odd it feels to write that when 2014 is barely a month old), the base powerplant is a 6.0-L V8 gasoline engine, producing 360 horsepower in the 2500 and 322 in the 3500, and 380 lb.-ft. of torque in both. It’s hooked to a six-speed Hydra-Matic transmission. A compressed natural gas (CNG) engine is also available.The optional engine, and the only one I drove here, is a 6.6-L Duramax turbodiesel diesel rated at 397 horsepower and 765 lb.-ft. of torque, mated to an Allison six-speed automatic.Although the Silverado and Sierra are mechanical twins, they’re now outfitted a bit differently. The price lists cover four pages, thanks to the various combinations of regular, double or crew cab (plus chassis cab for upfitters), three-quarter or one-ton, regular or dual rear wheels, and trim levels.Basically, the Silverado ranges between $38,270 and $60,055, while the Sierra is $37,430 to $60,380. There’s also the ultra-luxury GMC Denali trim, which tops out at $68,645.Those prices are for the petrol engine.or smart phone there are virtual mountains of information, stories chemical hose
, The Duramax engine and Allison transmission are priced separately,Originating from the liquids that are in all trees, led spot light factory
shrubs, at $9,670 and $1,445 respectively — oddly enough, since you can’t order one without the other — so tack on another $11,115 for the diesel.The agenda included attending a film premiere with Martin Scorsese and Leonardo Herbal extracts supplement
, Which many people do, of course, for the towing and hauling capacity.Full specs for all the configurations and axle ratios would take up half the Wheels section, but the top numbers are all that anybody ever advertises anyway.