The fourth generation of the C/K series is a range of trucks that was manufactured by General Motors. Marketed by the Chevrolet and GMC brands from the 1988 to the 2002 model years, this generation is the final version of the C/K model line. The C/K nomenclature itself became exclusive to Chevrolet, with the GMC division applying the GMC Sierra nameplate across its entire full-size pickup truck line. Internally codenamed the GMT400 platform, the fourth generation C/K was not given a word moniker (i.e., "Rounded-Line series"). After its production, the model line would informally become known by the public as the "OBS" (Old Body Style), in reference to its GMT800 successor.[3] Introduced in early 1987 for the 1988 model year, the fourth-generation C/K was initially produced as full-size pickup trucks and chassis cabs, later expanding to full-size SUVs. The model line would overlap production with both its predecessor and its successor. As with its predecessor, the fourth-generation C/K shared body commonality with GM medium-duty commercial trucks. After the 2000 model year, the fourth-generation C/K was discontinued and was replaced by the GMT800 platform (introduced for 1999); heavy-duty chassis cabs remained in production through 2002. In line with the GMC Sierra, Chevrolet adopted a singular Chevrolet Silverado nameplate for its full-size truck line (which remains in use). Over nearly a 14-year production run, the fourth-generation C/K was assembled by GM in multiple facilities in the United States, Canada, and Mexico.[4][5]