The Chevrolet Silverado is a range of trucks manufactured by General Motors under the Chevrolet brand. Introduced for the 1999 model year, the Silverado is the successor to the long running Chevrolet C/K model line. Taking its name from the top trim level from the Chevrolet C/K series, the Silverado is offered as a series of full-size pickup trucks, chassis cab trucks, and medium-duty trucks. The fourth generation of the model line was introduced for the 2019 model year. The Chevrolet Silverado shares mechanical commonality with the GMC Sierra; GMC ended the use of the C/K nomenclature a model generation prior to Chevrolet. In Mexico, high trim level versions of the Silverado use the Chevrolet Cheyenne name. Competing against the Ford F-Series, Ram Pickup, Nissan Titan, and Toyota Tundra, the Silverado is among the best-selling vehicles in the United States, having sold over 12 million examples since its introduction in 1999. History The Silverado nameplate made its debut for the 1975 model year, becoming the top trim level on all Chevrolet C/K trucks, slotted above Custom Deluxe, Scottsdale, and Cheyenne. At the same time, GMC C/K trucks used variations of the Sierra name (Sierra, Sierra Classic, Sierra Grande, and High Sierra). Today, Chevrolet still uses the CK and the CC in their current model codes to denote a 2-wheel rear drive (CC), or a four-wheel drive (CK). For the 1988 GMT400 model architecture, Chevrolet retained the C/K model nomenclature, with GMC branding its full-size line as Sierras. While sharing chassis and bodies, the model chronology of the Silverado and Sierra are different, with five generations of the Sierra and four of the Silverado. In 2018, at the NTEA Work Truck Show in Indianapolis, IN, Chevrolet unveiled the first medium-duty Silverado, expanding the model line to a 4500, 5500, and 6500 chassis cab. Largely the successor to the 2003-2010 GMT560 chassis, the medium-duty truck is exclusive to Chevrolet, with no plans for an equivalent GMC version. Instead, International would sell the Silverado Medium Duty as a rebadged counterpart, called the "CV". First-generation Silverado / second-generation Sierra (GMT800; 1999) The GMT800 Silverado/Sierra 1500 and 2500 pickup trucks were released in August 1998 as 1999 models. The "classic" light-duty GMT400 C/K trucks were continued in production for that first year alongside the new models, and the Heavy-Duty GMT400 pickups (alongside the GMT400 SUVs) were continued until 2000, with the new GMT800 Silverado/Sierra HD