GMC K2500 Truck

The K2500's Beginnings

GMC's K2500 is a mean truck that can handle even the most rugged terrain of the outdoors. Although GMC made trucks long before, the K1500's roots can be traced to the 1960 C/K pickup line manufactured by GM. Other than a name difference, both GMC and Chevrolet have produced nearly identical trucks since their inception. The "C" represented two-wheel drive, and, in both lines, the "K" represented four-wheel drive.  GMC used the numbers 1000, 1500, 2500, and 3000 to designate ½, ¾, 1, and 1 and ½ ton trucks, recpectively.

The K2500 initially came with stepside, which GMC called "Wideside," or fleetside, which GMC called "Fenderside," bed styles. The truck came with three engine choices:  a 235ci I6, a 283ci V8, or a 348ci V8. In an effort to create bigger trucks, the wheelbase length was expanded, a new drop-center frame was installed.  In 1964, the K models received 3.8L and 4.8L inline-six engines as the standard. This year was also the year the windshield changed to a curved form to provide better visibility and room inside the cabin.

The K2500 Built Throughout the Years

In 1967, the second generation saw some significant changes. A growing popularity in V8s lead to a larger big-block and a plethora of new engines to choose from. Some of these included a 230ci I6, 250ci I6, 250ci I6 OHV, 4.8ci I6, 307ci V8, 307ci V8 OHV, 327ci OHV, 327ci V8, and 396ci V8. The K1500 was now a half-ton truck, with the K2500 as the ¾-ton, and the K3500 as the 1 ton.  The K2500's height was lowered by five inches, rear coil spring suspensions became optional, while leaf springs remained standard, and a CST package was offered for the camper pickup.  In the next generation, the ‘70s supported a boxier look and feel to the truck. The flatter hood, sharply carved body, streamlined grille without the GMC initials, and sleeker windshield gave the K2500 a new image.  It had an all-wheel drive version, using a differential in the transfer case, and three new trim levels: the Sierra, Sierra Grande and High Sierra.   

In the late ‘70s, GM was the first company to offer a package with power windows and locks for trucks. However, the design generally remained unaltered other than a few comfortable interior upgrades. Due to government regulations and the energy crisis, most of the improvements were made on the engine. A truck that was still capable of tugging weight needed a fuel-efficient engine, so a powerful, electronic fuel-injected Vortec V6 was introduced as the new standard. A diesel engine was also introduced. In the ‘80s, an aluminum transfer case helped lower the weight, and the all-wheel drive was switched to part-time four-wheel drive. In 1981, an all-new transfer case allowed shifting from two-wheel drive to four-wheel drive at speeds under 25 mph.  Automatic front locking hubs were included with the new system.

During this time, for one year in 1987, the "C/K" nomenclature was switched to "R/V," while GMC worked on a new version of the C/K platform.   The older style continued to be built as R/V models until 1991.  The new trucks were built upon the GMT400 platform with longer bodies, and they stood for the same thing: "R" for 2WD and "V" for 4WD. Headlights were changed to a rectangular shape, the interior was enlarged, and the "Shift-On-The-Fly Insta-Trac" allowed the truck to switch its drivetrain system at any speed. In 1988, GMC brought back the "C/K" nomenclature. A Work Truck model was introduced in the 1990, and throughout the decade the C/K line improved its safety features with better steering, lower side view mirrors, four-wheel antilock brakes, and airbags on all sides. Three-door models were introduced in the late ‘90s, as well as the standard Vortec 4300 that could reach up to 200 horsepower. By the end of the decade, the C/K models were known for their satisfaction, innovation, and tough handling for the outdoors. They had such a loyal fan base that despite the fact the Sierratook over production in 1999, a few models were produced in the early 2000s.

Did You Know?

In 1960, "C" and "K" weren't the only designated letters for GM trucks. There was also a "P" model that represented forward control, an "L" model which indicated low cab forward, an "S" that stood for school bus, and an "M" that stood for tandem axle models.