Chevrolet C/K

Chevrolet C/K

Manufacturer	General Motors
Also called	GMC C/K GMC Sierra
Production	1960–2000 United States 1965–2000 Canada 1964–2001 Brazil 1975–1982 Chile 1960–1978/1986–1994 Argentina (Sevel) 1992-2005 South Korea
Predecessor	Task Force
Successor	Chevrolet Silverado/GMC Sierra
Class	Full-size pickup truck
Body style	2-door regular cab 2-door extended cab 3-door extended cab 4-door crew cab
Layout	Front engine, rear-wheel drive / four-wheel drive

The C/K is the name for Chevrolet and GMC's full-size pickup truck line from 1960 until 1999 in the United States, from 1965 to 1999 Canada, from 1964 through 2001 in Brazil,from 1975 to 1982 in Chile, from 1992 to 2005 in South Korea. The first Chevrolet pickup truck appeared in 1924, though in-house designs did not appear until 1930. "C" indicated two-wheel drive and "K" indicated four-wheel drive. The aging C/K light-duty pickup truck was replaced with the Chevrolet Silverado and GMC Sierra names in 1999 in the US and Canada, and 2001 in Brazil; the Chevrolet Silverado HD and GMC Sierra HD heavy-duty pickup trucks followed in 2001. Until this time the names Silverado and Sierra were used to identify the trim level of the C/K trucks.

For the first Chevrolet C Series, made from 1911 to 1913, see Chevrolet Series C Classic Six, (the first Chevy).

First generation 1960–1966

First generation

Also called	C10/K10 C15/K15 C20/K20 C30
Production	1960–1966
Engine	230 in³ (3.8 L) I6 236 in³ (3.9 L) I6 250 in³ (4.1 L) I6 261 in³ (4.3 L) I6 292 in³ (4.8 L) I6 305 in³ (5.0 L) V6 283 in³ (4.6 L) V8 327 in³ (5.3 L) V8 GVWR5000 lbs
Transmission	3-speed synchromesh manual 4-speed synchromesh manual 2-speed Powerglide automatic
Wheelbase	115 in (2,921 mm) (short box) 127 in (3,226 mm) (long box)

The 1960 model year introduced a new body style of light pick-up truck that featured many firsts. Most important of these were a drop-center ladder frame, allowing the cab to sit lower, and independent front suspension, giving an almost car-like ride in a truck. Also new for 1960 was a new designation system for trucks made by GM. Gone was the 3100, 3200, and 3600 designations for short 1/2, long 1/2 and 3/4-ton models. Instead, a new scheme would assign a 10, 20, or 30 for 1/2, 3/4, and 1-ton models. Since 1957, trucks were available from the factory as 4-wheel drive, and the new class scheme would make this known. A C (Conventional) in front of the series number would indicate 2-wheel rear drive while a K would denote 4-wheel drive. Actual badging on trucks still carried the series name system from the previous generation. The 10, 20, 30, and 40 series (C or K) were badged as "Apache", etc. 50, and 60 series trucks were badged as "Viking", and the largest 70, 80, and 90 series models were marked "Spartan" etc. in 1960, C/K trucks were available in smooth "Fleetside" or fendered "Stepside" versions. GMC called these "Wideside" and "Fenderside." Half-ton models were the C10 and K10 short-bed trucks, and C15 and K15 long-bed trucks. The 3/4-ton C20 and K20, as well as the one-ton C30, were also available. GMC did not use the "C" nomenclature, though their 4x4 versions had the "K" designation. GMC Model numbers for 1/2, 3/4, 1, and 1.5 ton were 1000, 1500, 2500, and 3000. The 1960,1961, & 1962 model used torsion bar front suspension, with trailing arm suspension rear. Trim lines were base and "Custom." Engines included the base GMC 305 in³ V6 for the GMC version, 135 hp (101 kW) 236 in³ (3.9 L) and 150 hp (112 kW) 261 in³ (4.3 L) straight-6s, and a 283 in³ (4.6 L) V8 with 185 hp (119 kW).

A coil-spring front suspension came in 1963; along with a new base engine, a 140 hp (104 kW) 230 in³ (3.8 L) I6, and an optional 165 hp (123 kW) 292 in³ (4.8 L) I6. The cab was changed for 1964, with elimination of the "wraparound" windshield and a new front grille design, along with various interior changes. Air conditioning and a 220 hp (164 kW) 327 in³ (5.3 L) V8 came in 1965. A new base engine finished the model in 1966 with a 155 hp (116 kW) 250 in³ (4.1 L) I6.

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  1966 Chevrolet C-10

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  1963 Chevrolet stepside

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  1962 Chevrolet C/K

Second generation 1967–1972

Second generation

Production	1967–1972
Assembly	Atlanta, GA Baltimore, MD Pontiac, MI Flint, MI Tarrytown, NY Kansas City, MO St. Louis, MO Janesville, WI Norwood, OH Fremont, CA Ulsan, South Korea Oshawa, ON Buenos Aires, Argentina
Engine	250 cu in (4.1 L) I6 292 cu in (4.8 L) I6 283 cu in (4.6 L) V8 307 cu in (5.0 L) V8 327 cu in (5.4 L) V8 350 cu in (5.7 L) V8 396 cu in (6.5 L) V8 402 cu in (6.6 L) V8 GMC models continued to offer the 305 and 351 c.i. V6s through 1970.
Transmission	3-speed manual 4-speed Muncie SM465 manual 4-speed New Process NP435 manual 2-speed Powerglide automatic 3-speed THM-350 automatic 3-speed THM-400 automatic
Wheelbase	115 in (2,921 mm) (short box) 127 in (3,226 mm) (long box) 133 in (3,378 mm) (Longhorn)
Length	188.5 in (4,788 mm) (short box) 207.75 in (5,277 mm) (long box) 213.75 in (5,429 mm) (Longhorn Fleetside) 217.75 in (5,531 mm) (Longhorn Stepside)

1967 Chevrolet C/K

1967 GMC C/K

1968 GMC C/K

71-72 Chevrolet C-10 Cheyenne

Chevrolet C/K

A new, more modern look came in 1967, along with a new nickname: "Action Line". It was with this revision of the C/K truck that General Motors began to add comfort and convenience items to a vehicle line that had previously been for work purposes alone. The majority of 10 and 20 series Chevrolet trucks from 1967 to 1972 were built with a coil spring trailing arm rear suspension, which greatly improved the ride over traditional leaf springs. However, the leaf spring rear suspension was still available on those trucks, and standard on 30 series trucks. GMC models came standard with leaf springs with coils springs optional; all four-wheel drive models (Chevrolet and GMC) had leaf springs on both axles. This was the only year of the "small rear window"; it was replaced with larger rear glass in 1968. The standard drivetrain came with a three speed manual transmission and one of two engines; the 250 in³ straight six or the 283 cu in (4.6 L) V8. The optional transmissions were the four speed manual, the Powerglide and the Turbo-Hydramatic 350 and 400. The 292 six and the 327 in³ V8 were the optional engines. The 1/2 ton trucks came with a 6 x 5.5" bolt pattern, the 3/4 and 1 ton trucks came with an 8 x 6.5" bolt pattern.

In 1968, the 283 cu in (4.6 L) V8 was replaced with a 307 cu in (5.0 L) and a 310 hp (231 kW), 396 cu in (6.5 L) V8 was offered for the first time. The most visible change in differentiating a 1968 from a 1967 was the addition of side-marker reflectors on all fenders. Also, the small rear window cab was no longer available. The GMC grille was revised, with the letters "GMC" no longer embossed in the horizontal crossbar. Another addition was the Custom Comfort and Convenience interior package that fell between the Standard cab and CST cab options. In 1968, Chevrolet celebrated 50 years of truck manufacturing, and to commemorate, they released a 50th Anniversary package, which featured an exclusive white-gold-white paint scheme. Also in 1968, the Longhorn model debuted on 3/4 ton trucks. Featuring a 133" wheelbase identical to the one ton vehicles, it added an extra 6" to the bed. Longhorns, interestingly, were 2wd only; no factory Longhorn 4x4 was built.

The 327 c.i. V-8 engine was enlarged in 1969 to 350 CID (stroke increased from 3.25 to 3.48) with a net horsepower rating of 195-200, depending on emissions package 255 hp (190 kW), 350 cu in (5.7 L). Along with the new engines came a new grille design for Chevrolet trucks and a more upright hood for both Chevrolet and GMC trucks. A utility variant, known as the K5 Blazer, was also introduced with a shorter wheelbase of 104 inches (2,642 mm). The GMC version, known as the Jimmy, was introduced the same year. Some internal cab changes were also made, most notably the switch from a hand-operated parking brake to a foot pedal, and a more modern looking two-spoke steering wheel with plastic horn button replaced the previous year's three-spoke wheel with chrome horn button. Also new this year were upper and lower side moldings, which added another two-tone paint option. These were standard on CST trucks, and optional in any other trim level.

1970 GMC C/K

The only noticeable change for 1970 was a minor update to the Chevrolet grille. At first glance, the 1969 and 1970 grilles appear identical. However, the 1970s plastic inserts actually have highlights that break the appearance into six separate sections. The 396, while still sold as such, was enlarged to 402 cubic inches starting in 1970.

Several changes occurred in 1971. First came another new grille design (the "egg crate") for Chevrolet trucks and black paint over portions of the GMC grille. Second, an additional trim package was introduced: the Cheyenne. On GMC models, this was referred to as the Sierra. These packages consisted mostly of comfort features — nicer interiors, more padding and insulation, carpet, chrome trim, and upper and lower side molding and tailgate trim. 1971 was the first year for AM/FM radios factory installed. Finally, the front brakes on all light-duty trucks were switched from drum brakes to disc brakes, resulting in much less brake fade under heavy use. While many prior C/K half-ton trucks had used a six-lug bolt pattern (6 x 5.5") for the wheels, two-wheel-drive models switched to a five-lug pattern (5 x 5" bolt circle) common to Buick, Oldsmobile, Pontiac, and Cadillac passenger cars. The 1/2 ton 4 x 4 retained the 6 lug bolt pattern. This bolt pattern would remain the standard through the end of the C/K series (along with the Chevrolet/GMC vans). Also, Chevrolet changed the 396 V8 emblem designation to 400 V8.

1972 GMC Sierra Custom Camper

The 1972 models were virtually identical to 1971 models, with the only change being the rear view mirror was glued to the windshield instead of being bolted to top of the cab, and metal or vinyl-covered flat door panels were no longer available; all trim level door panels were molded plastic with integral armrests and wood grain inserts on Cheyenne and Sierra trim levels. For restoration, it should also be noted that the door and window cranks were slightly longer due to the molded plastic door panels, and the vent windows were now secured with a single screw on the inside of the door, thus differentiating it from the 1971 model year.

Engines

Year	1967	1968	1969	1970	1971	1972
Inline 6	250 in³ 292 in³	250 in³ 292 in³	250 in³ 292 in³	250 in³ 292 in³	250 in³ 292 in³	250 in³ 292 in³
V6 (GMC)	305 in³ 351 in³	305 in³ 351 in³	305 in³
V8	283 in³ 327 in³	307 in³ 327 in³ 396 in³	307 in³ 350 in³ 396 in³	307 in³ 350 in³ 396 in³	307 in³ 350 in³ 402 in³	307 in³ 350 in³ 402 in³

Trim Levels (Chevrolet)

Years	Base	Mid-level	Top-line	Special
1967-70	C/10	Custom/10	CST/10
1971	Custom/10	CST/10	Cheyenne/10
late 1971-72	CST/10	Cheyenne/10	Cheyenne Super	Cheyenne Highlander

A 10, 20, or 30 on the emblem indicates 1/2, 3/4, or 1 ton trucks.

Trim Levels (GMC)

Years	Base	Mid-level	Top-line	Special
1967-70	1500	Custom 1500	Super Custom 1500
1971	Custom 1500	Super Custom 1500	Sierra 1500
late 1971-72	Super Custom 1500	Sierra 1500	Sierra Grande 1500	Sierra Highlander

1500, 2500, and 3500 designations were used to indicate 1/2, 3/4, and 1-ton trucks.

In both series, the 'Highlander package' included special color-coordinated houndstooth cloth inserts and additional trim colors and insulation.

Third generation 1973–1987

Third generation

Also called	Chevrolet Scottsdale Chevrolet Custom Deluxe
Production	1973–1987
Assembly	Atlanta, Georgia Baltimore, Maryland Pontiac, Michigan Flint, Michigan Tarrytown, New York Kansas City, Missouri St. Louis, Missouri Janesville, Wisconsin Norwood, Ohio Fremont, California Oshawa, Ontario Córdoba (Argentina) Arica, Chile (1975–1982)
Engine	250 cu in (4.1 L) I6 292 cu in (4.8 L) I6 262 cu in (4.3 L) V6 305 cu in (5.0 L) V8 350 cu in (5.7 L) V8 400 cu in (6.6 L) V8 454 cu in (7.4 L) V8 350 cu in (5.7 L) Oldsmobile Diesel V8 379 cu in (6.2 L) Detroit Diesel V8
Transmission	3-speed Turbo Hydra-Matic 350 automatic 3-speed Turbo Hydra-Matic 400 automatic 4-speed Turbo Hydra-Matic 700R4 automatic 3-speed Saginaw manual 4-speed Saginaw Muncie SM465 manual 4-speed New Process NV833 overdrive manual
Wheelbase	117.5 in (2,985 mm) 131.5 in (3,340 mm) 164.5 in (4,178 mm)
Length	188.5"(1971), 191.5"(1975), 211.8"

Facelifted GMC C/K

GMC K3500 Sierra Classic

An all-new clean sheet redesign of General Motors' Chevrolet and GMC brand C/K-Series pickups débuted in 1972 for the 1973 model year. Development of the new third generation trucks began in 1968, four years prior to production in 1972, with vehicle components undergoing simulated testing on computers, before the first prototype pickups were even built for real world testing. The redesign was revolutionary in appearance at the time, particularly the cab, departing from typical American pickup truck designs of the era. Aside from being near twins, the Chevrolet and GMC pickups looked like nothing else on the road. As a result, the third generation trucks are officially known as the "Rounded-Line" generation. Some people may refer to them as "square bodys", given that the trucks appear square-like when compared to more modern automotive design standards.

GM's design engineers fashioned the "Rounded-Line" exterior in an effort to improve aerodynamics and fuel efficiency, using wind tunnel technology to help them sculpt the body. Third generation design traits include "double-wall" construction, sleek sculpted body work, flared secondary beltline and an aerodynamic cab which featured rounded doors cutting high into the roof and steeply raked windshield featuring an available hidden radio antenna embedded into the glass.

There were two types of pickup boxes to choose from. The first type, called Fleetside by Chevrolet and Wideside by GMC, was a "double-wall" constructed full width pickup box and featured a flared secondary beltline to complement the cab in addition to new wraparound tail lamps. Both steel and wood floors were available. The second type, called Stepside by Chevrolet and Fenderside by GMC, was a narrow width pickup box featuring steps and exposed fenders with standalone tail lamps. Initially, only wood floors were available.

The wheelbase length was extended to 117.5 in (2985 mm) for the short wheelbase pickups, and 131.5 in (3340 mm) for the long wheelbase pickups. A new dual rear wheel option called "Big Dooley" was introduced on one-ton pickups, along with a new Crew Cab option on the 164.5 in (4,178 mm) wheelbase. Crew Cabs were available in two versions: a "3+3" which seated up to six occupants and "bonus cab" which deleted the rear seat and added rear lockable storage in its place. The fuel tank was moved from the cab to the outside of the frame, and a dual tank option was available which brought fuel capacity to 40 US gallons. 1980 was the first year that a cassette tape player could be purchased, along with a CB radio.

The Rounded-Line generation ultimately ran for a lengthy 15 model years (1973–1987) with the exception of the Crew Cab, Blazer, Jimmy, and Suburban versions, which continued up until the 1991 model year.

Interior and safety

The third generation pickups were offered in several equipment level packages or trim packages. Chevrolet/GMC used various names for the trim levels throughout the vehicle’s life cycle and some were rearranged in their class order. For the 1973 and 1974 model years, the base (standard) trim level was Custom/Custom, mid-range trims were Custom Deluxe/Super Custom, luxury trims were Cheyenne/Sierra, and top-of-the-line luxury trim levels were Cheyenne Super/Sierra Grande.

For the 1975 model year the trim levels were revised and the base trims were now Custom Deluxe/Sierra, mid-range trims were Scottsdale/Sierra Grande, luxury trims were Cheyenne/High Sierra, and the top-of-the-line luxury trim levels were now known as Silverado/Sierra Classic. They remained in this configuration up to the 1987 model year. For the 1982 model year, the luxury trim levels were dropped, leaving the base, mid-range, and top-of-the-line luxury trim level packages.

Soft touch materials were used throughout the passenger cabin, such as the dashboard, doors (arm rests), steering wheel, and shift levers. Subtle grained interior panels and bright metal work was used on the inside with high-quality materials also used on the outside, like chrome, aluminium, and polished stainless steel, particularly on top-of-the-line luxury Silverado or Sierra Classic trim levels. Custom Vinyl vinyl or soft Custom Cloth cloth and velour seating surfaces were used along with fabric headliners, door inserts, and plush carpeting, depending on the trim level. Upper class trim levels also used acoustic deadening materials for quieter ride comfort. From model years 1973 to 1977, chestnut wood grain inserts were used on the dashboard and doors for further visual enhancement. The wood grain inserts were replaced by bright brushed aluminium inserts for model years 1978 to 1987. A Delco AM/FM audio sound system and an all-season climate control system that heated, cooled, cleaned, and dehumidified were optional extras.

At its launch in 1972, the Rounded-Line C/K-Series introduced two firsts in safety advancements concerning full-size pickups, and would later lead a third safety advancement in 1975. The first was the standard passenger-side sideview mirror, and the second was the energy-absorbing collapsible steering column. Patented by GM and already in use in its cars since 1967, the new energy-absorbing steering column was standard on all C-Series and K-Series models.

The third safety advancement was the introduction of dual front lap-and-shoulder safety belts with emergency locking retractors for outboard occupants in 1975 for the 1976 model year. These replaced the outdated and inadequate lap belts previously used. A center lap safety belt with slack adjustment was provided for the center occupant. Ford and Dodge would follow one model year later adding lap-and-shoulder safety belts to their pickups.

Other safety features included soft-padded interior panels for appearance and safety, 3,329 square inches of tempered and laminated safety glass, prismatic rearview mirror, six turn-signal indicator lamps with asymmetrical flash, four-way hazard function, and lane departure function.

Chassis and powertrain

Third generation Rounded-Line C/K-Series pickups gained an all-new, high tensile strength carbon steel ladder type frame with "drop center" design. Steering controls included variable-ratio recirculating ball steering gear with optional hydraulic power assist. Braking controls included front self-adjusting disc brakes with rear finned drum brakes and optional four-wheel hydraulic Hydra-Boost or Vacuum-Boost power assist. Engines choices initially consisted of six or eight cylinder engines with either manual or Turbo Hydra-Matic transmissions.

C-Series pickups included two-wheel drive and featured an independent front suspension (IFS) system with contoured lower control "A" arms and coil springs. GM's new Load Control rear suspension system took up residence in the back. The Load Control rear suspension system consisted of a rear live axle with dual stage Vari-Rate multi-leaf springs and asymmetrical (offset) shock absorber geometry, to help sort out any "wheel hop" under heavy loads or hard acceleration.

K-Series pickups included either Conventional, Permanent, or Shift-on-the-move four-wheel drive. The latter system was introduced for 1981. Regardless of the type of four-wheel drive system equipped, all K-Series pickups featured four-corner Vari-Rate multi-leaf springs, front live axle with symmetrical (inline) shock absorber geometry, and the Load Control rear suspension system. K-Series pickups also featured an off road oriented design, with the transfer case bolted directly to the transmission and running gear tucked up as high as possible under the vehicle to reduce the chances of snagging vital components on obstacles, as well as to achieve a low silhouette and optimal ground clearance. Exposed brake lines wrapped in steel were standard, with underbody skid plate armor optional for further protection.

Conventional four-wheel drive pickups featured manual locking hubs and a two-speed dual range New Process 205 transfer case with four drive modes: Two High, Four High, Neutral, and Four Low. Two High gave a 0:100 torque split, while Four High yielded a locked 50:50 torque split. Four Low applied reduction gearing. The front and rear propeller shafts were locked at all times in Four High and Four Low. Neutral allowed for flat towing, or use of the power take off (PTO).

Permanent four-wheel drive pickups featured a two-speed dual range New Process 203 transfer case with planetary center differential and lock. Five drive modes were provided: High, Low, Neutral, High Loc, and Low Loc. In High the center differential was unlocked and allowed the front and rear propeller shafts to slip as needed for full-time operation. The system could be manually shifted into High Loc which locked the center differential for a locked 50:50 torque split. Low and Low Loc applied reduction gearing with or without lock, depending on the mode selected. Neutral was also available for use of the PTO.

A new Eaton Automatic Differential Lock (ADL) was introduced in 1973 as an optional extra on the Rounded-Line C/K-Series pickups, for the rear hypoid differential. The new automatic locking differential was offered under the G86 code, replacing the Eaton NoSpin differential, and eventually replacing the old Positraction limited-slip differential in 1974, at which point it assumed the G80 code. The Eaton ADL featured intelligent differential control via an internal governor which monitored vehicle speed and wheel slip to know when to automatically lock and could lockup 100 percent at or below 20 mph (32 kph) increasing tractive effort. The differential lock would unlock and deactivate at speeds above 20 mph for safety reasons, such as the vehicle being on dry pavement.

Towing and payload capacity ratings for Rounded-Line C/K-Series pickups varied, depending on how they were configured. Factors such as engine and transmission combination, differential gear ratio, curb weight, and whether the pickup was two-wheel drive or four-wheel drive decided how much the pickup could safely tow or haul.

A properly equipped C-Series half-ton class pickup could tow up to 8,000 lbs (4 tons) of braked trailer, while a properly equipped C-Series three quarter-ton or one-ton class pickup could tow up to 12,000 lbs (6 tons) of braked trailer. Adding four-wheel drive reduced towing capability due to increased curb weight, which resulted from additional driveline components (transfer case, front axle, front differential, front propeller shaft, and so on) needed to facilitate four-wheel drive. A properly equipped K-Series half-ton or three quarter-ton class pickup could tow up to 6,500 lbs (3.25 tons) of braked trailer, whilst a properly equipped K-Series one-ton class pickup could tow 500 lbs more, up to 7,000 lbs (3.5 tons) of braked trailer. The decreased towing capability of K-Series pickups, when compared to their C-Series pickup siblings, is a valid tradeoff for all-weather, all-terrain capability.

Heavy-duty towing equipment was available for both C and K-Series pickups, such as the Trailering Special package (included power steering, uprated battery, and uprated generator), 7-pin trailer electrics connector, heavy-duty engine oil cooler, heavy-duty transmission oil cooler, and a weight distributing trailer hitch.

For the 1975 model year, the 185 hp 400 cu in (6.6 L) small-block V-8 was added to the line and there was a realignment of Chevy trim levels, along with new grilles and clear/white instead of orange front turn signals. Base models gained a passenger-side woodgrain dash accent and a new plaid upholstery pattern (which would change slightly each year until 1978).

A new gauge to show voltage replaced the ammeter in 1976, and the engine size decals were removed from the grille during this model year.

For 1977 models, power windows and power door locks were introduced as an optional extra. There was another round of new grilles, revised inner door panels that left less metal exposed, a four-wheel drive, full one-ton chassis was added to the lineup, and a Dana 60 was used for the front axle, as well as an electric oil pressure gauge replacing the mechanical unit. Trucks with an optional trim level, but without an additional wheel upgrade, received flatter stainless steel hubcaps, still with painted accents. This was also the only year with yellow painted trim instead of black.

The addition of the 125 hp 350 cu in (5.7 L) Oldsmobile diesel V-8 began in 1978. All models got new, flatter dash trim panels, black on the lower two trims and aluminum-look on the fancier two. Base models received the flatter stainless hubcaps, and Stepsides got new squared-off taillights with built-in backup lights and side markers, while the rear fenders were smoothed out where the old side markers were.

The 1979 models got a new grille surround that incorporated the turn signals; inside there was a new full-width "houndstooth" seat trim on base models and a (rare) fifth interior color option on the higher series called "oyster" by Chevrolet and "Mystic" by GMC (mostly white with a gray dash, carpeting and cloth).

For the 1980 model year, permanent four-wheel drive was discontinued on K-Series, leaving only conventional four-wheel drive. Some pickups gained a new grille, others did not; high-trim Chevys had both a new surround that incorporated near-flush square headlights and revised turn signals with a new, squarer grille pattern, while a GMC base model was entirely carryover, base Chevys had the new center section in the 1979 surround while GMCs with uplevel trims or the separate RPO V22 option had the new square-light surround with the main grille introduced in 1977. Blue interiors were a darker shade than before.

1981 mid-life cycle facelift

A mid-life cycle cosmetic facelift and mechanical refresh was carried out for the 1981 model year. In response to the recent 1979 energy crisis, the 1981 rework featured several fuel saving techniques to help make the Rounded-Line C/K-Series pickups more fuel efficient. Again, engineers turned to wind tunnels to resculpt the front end with new sheet metal, reducing areas which could hinder air flow and cause drag. A sleeker front bow-like look emerged, similar to a ship’s bow with the front end being gently swept back from the center. New dual tier halogen headlamps became available with the Deluxe Front Appearance package. Mechanical updates included more anti-corrosion techniques, reduced weight, and a new 5.0 L 305 cubic inch V-8 with electronic spark control. The 5.7 L 350 cubic inch pushrod V-8 was dropped from the half-ton class pickups, except in California where it was offered in place of the new 5.0 L 305 engine with electronic spark control, which did not meet California's emissions requirements.

A new Shift-on-the-move four-wheel drive system with two-speed dual range New Process 208 aluminium transfer case was introduced on K-Series pickups for the 1981 model year. It replaced the permanent four-wheel drive system, on pre-1980 models. The shift-on-the-move four-wheel drive system featured new automatic self locking hubs and synchronized direct high range planetary gearing, such that the truck could be shifted from two-wheel drive, to fully locked four-wheel drive at speeds of up to 25 mph. Once the shift from two-wheel drive to four-wheel drive was made, the vehicle could be driven at any forward or reverse speed. Four drive modes were offered: Two High, Four High, Neutral, and Four Low. Two High gave a 0:100 torque split, with Four High yielding a locked 50:50 torque split through direct synchronized gearing. Four Low applied reduction gearing. The front and rear propeller shafts were locked at all times in Four High and Four Low. Neutral was provided for disengagement of both propeller shafts. Conventional four-wheel drive was still available with manual locking hubs.

A new four-speed Turbo Hydra-Matic 700R4 transmission with overdrive gearing became available in 1981 for the 1982 model year. The 151 hp 379 cu in (6.2 L) Detroit Diesel V-8 was added to replace the LF9 Oldsmobile diesel. Chrome front bumpers were now standard on base models.

1985 saw the new 262 cu in (4.3 L) LB1 introduced to replace both inline-six engines. Hydraulic clutches were introduced. Also, a new grill was used. The most expensive radio was the AM/FM stereo seek/scan with cassette tape at $594. A variation of the C/K series was introduced in 1985 in Brazil, replacing the locally-produced C10, introduced in 1964.

R/V-Series

For the 1987 model year, the last model year for the conventional cab pickups, the Rounded-Line C/K-Series were renamed the R/V-Series. R-Series now designated two-wheel drive, while V-Series represented four-wheel drive. The name change is also found in the vehicle identification number. This was done in preparation for the next generation GMT400 trucks, which were produced concurrently with the older line. The new 1988 model trucks entered production December 8, 1986 at Pontiac East, Oshawa, and the new Fort Wayne plant. The 1987 models continued to be built at Janesville, St. Louis, and Flint.

Along with the name change, came other major improvements and tweaks for the final model year of the conventional cab pickups. Single-point electronic throttle-body fuel injection (TBI) was introduced on GM's full-size pickups, with new electric fuel pumps and high-pressure fuel lines. In addition, a "smart" powertrain control module (PCM) was also introduced, which controlled the fuel injection system, fuel-to-air burn ratio, engine ignition timing, and (if equipped with an automatic transmission) the Turbo Hydra-Matic’s turbine torque converter clutch. The 5.7 L 350 cubic inch pushrod V-8 was reintroduced to the order books for R-Series and V-Series half-ton class pickups, with the new TBI fuel injection system. Horsepower and torque output was increased to 210 hp, and 300 lb-ft of torque.

After 1987, R/V remained in use for the Rounded-Line one-ton crew cab pickups through 1991 (built at Janesville), and the Rounded-Line utilities (Chevrolet K5 Blazer and Suburban, built at Flint) through 1991. From the 1988 model year and onward, C/K was re-used for the fourth generation "GMT400" design.

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  1979 GMC K15 Sierra Grande Regular Cab Short Bed Stepside

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  Pre-facelift Chevrolet C/K

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  Pre-facelift GMC C/K

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  1973 GMC C/K

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  1977 Chevrolet C/K Cheyenne

Sidesaddle fuel tank controversy

The third generation of GM's full-size pickup line featured a design improvement that saw some criticism long after the model run ended. The fuel tank was relocated from the cab to the outboard sides of one or both frame rails beneath the cab floor extending under the leading edge of the pickup box, commonly referred to as a sidesaddle arrangement. This enlarged fuel capacity from 16 up to 40 gallons depending on wheelbase and the number of tanks. This also removed the tank from the passenger compartment.

According to a now debunked 1993 report which aired on Dateline NBC, this arrangement made the trucks capable of exploding when involved in a side collision. The faked video was staged by an expert witness for hire against GM, Bruce Enz of The Institute for Safety Analysis. Enz used incendiary devices and a poorly fitted gas cap to create the impression of a dangerous vehicle. It was also revealed that the Dateline report was dishonest about the fuel tanks rupturing and the alleged 30 mph (48 km/h) speed at which the collision was conducted. The actual speed was found to be higher, around 40 mph (64 km/h), and after x-ray examination of the fuel tanks from the C/K pickups used in the staged collision, it was discovered they had not ruptured and were intact. GM filed suit over NBC's false report, with the broadcaster settling the same day.

Fatality figures vary wildly. A study by Failure Analysis Associates (now Exponent, Inc.) found 155 fatalities in these GM trucks between 1973 and 1989 involving both side impact and fire. The Center for Auto Safety, Ralph Nader's lobbying group, claims "over 1,800 fatalities" between 1973 and 2000 involving both side impact and fire. Other commentators noted that regardless of any increased risk of fire, the GM trucks had statistically indistinguishable safety records in side-impact crashes from their Ford and Dodge equivalents.

Also notable, was the fact that the sidesaddle fuel tanks themselves, were found to have a well-engineered robust design and form factor, which was highly resistant to crushing or crumpling from a side-impact. The heavy-duty design of the sidesaddle fuel tanks allowed them to not only comply with, but also far exceed the U.S. government's safety standards, which specifically address the dangers of fuel tank rupturing in side collisions. Studies showed that it would take about 4,000 side-impact crashes with a Rounded-Line GM pickup to get one with fire, major injury, or fatality.

In 1993 the bad publicity generated by the later debunked Dateline story spawned several class action lawsuits. As settlement GM offered owners $1000 coupons toward the purchase of a new truck with a trade-in of the old one. Even though the trucks met NHTSA 15 and 20 mph side impact crash test standards in place at the time of manufacture, GM eventually settled with the NHTSA in 1994 for the amount of $51 million to be used for safety programs. The fourth generation C/K-Series pickups (1988–2001) were designed and produced well before the lawsuits, with one fuel tank inside the frame rails.

Foreign production

Sevel Argentina S.A. built the Chevrolet C10 in their Córdoba plant from 1985 to 1991. The gasoline version used the Chevy 250 CID engine (4,093 cc) familiar to most Latin American markets, producing 130 hp. Because of Sevel being a subsidiary of Peugeot, the C10 was also available with a 70 hp Indénor XD2 2,304 cc diesel engine, perhaps best known in the US from the Peugeot 504.

Fourth generation 1988–1998/1999/2000

Fourth generation / GMT400

Also called	Chevrolet Silverado GMC Sierra
Production	1988–2000
Assembly	Oshawa, Ontario Pontiac, Michigan Flint, Michigan Fort Wayne, Indiana
Platform	GMT400/480
Engine	250 cu in (4.1 L) I6 (Brazil) 262 cu in (4.3 L) V6 305 cu in (5.0 L) V8 350 cu in (5.7 L) V8 454 cu in (7.4 L) V8 378 cu in (6.2 L) diesel V8 6.5 L turbo diesel V8
Transmission	3-speed THM-400 automatic 4-speed 700R4 automatic 4-speed 4L60 automatic 4-speed 4L60-E automatic 4-speed 4L80-E automatic 4-speed SM465 manual 5-speed NV3500 manual 5-speed NV4500 manual HM290 manual 5 speed 5LM60 manual 5 speed
Wheelbase	117.5 in (2,985 mm) 131.5 in (3,340 mm) 141.5 in (3,594 mm) 155.5 in (3,950 mm)
Length	194.5 in (4,940 mm) 213.1 in (5,413 mm) 218.5 in (5,550 mm) 237.4 in (6,030 mm)
Width	76.8 in (1,951 mm) 77.1 in (1,958 mm)
Height	73.2 in (1,859 mm) 72.6 in (1,844 mm)

Introduced in April 1987 as 1988 models (known as the GMT400 platform), there were eight different versions of the C/K line for 1988: Fleetside Single Cab, Fleetside Extended Cab, Fleetside Crew Cab, and Stepside Single Cab, each in either 2WD (C) or 4WD (K) drivelines. All C/K models would ride on independent front suspension. Three trim levels were available: Cheyenne, Scottsdale, and Silverado. Engines were a 160 hp (119 kW) 4.3 L V6, a 175 hp (130 kW) 5.0 L V8, a 210 hp (157 kW) 5.7 L V8 and a 6.2 L diesel V8. A 230 hp (172 kW) 7.4 L V8 was available in the 3/4-ton and one-ton trucks.

4x4 front suspension

A drastic difference between the 3rd generation and 4 generation GM trucks was the suspension. 3rd Generation 4x4 trucks used solid front axles. The 4 generation GM trucks used independent front suspension (IFS).

In 1989, a half ton 2WD fleetside Sport appearance package was available with black and red bumper and body trim, and a black grille with red outlined Chevrolet emblem, chrome wheels with custom center caps, and fog lights. The 89 was a limited production run set to determine how well the "sport" package would be received by consumers in the years to follow. The Sport package was more of a trim and towing package edition as well as a few engine enhancements that weren't on available on other Chevrolet trucks of the time.

Also in '89, the 4x4 sport appearance package included black bumper and body trim, wheel flares, mirrors, sport grille, 16" cast aluminum wheels and special "4x4" badging on the box and "SPORT" badged on the tailgate. The box and tailgate decals were flanked by red outlined Chevy bowties. The sport package was only offered from 1989 until 1992 as some insurance companies began to express concerns with the idea of a high performance truck. RPO code was BYP. This model was only available with the standard cab and regular fleet-side box. Colors included white, black, and red. A Z71 off-road package was also available with skid plates and Bilstein shocks. The Work Truck (W/T) was also introduced in 1990, which featured a single cab long bed with Cheyenne trim and new grille with black bumpers. Also in 1988 the GMC 3500 EFI with a powerful 454 (7.4 L) was available. The 454 EFI produced 230 hp (172 kW) and 385 lb·ft (522 N·m). In 1991, the 4L80-E automatic transmission was available for the 3/4-ton and one-ton trucks. In 1995, the 4-speed manual transmission was dropped and the stepside trucks were available with extended cabs. The 6.5 L diesel V8 was also made available with a turbocharger. In 1993, the Sport package was available for the step-side models, featuring body-colored bumpers, mirrors, and grille with cast aluminum wheels. The 700R4 transmission was replaced with the 4L60-E automatic in 1993 also. In 1996, the 6.2 L diesel V8 was dropped. 1994 saw new grills on both the Chevrolet and GMC trucks. In 1995, the trucks received an updated audio system and interior (including full instrumentation with tachometer standard). Four wheel ABS brakes were standard in 1995 as well as a driver's side airbag on the 1/2 ton models. The Vortec V8s were introduced in 1996, with power boosts across the board for the gasoline engines. The Vortec V8's made between 255 to 290 horsepower, thanks to high-flow cylinder heads, new camshaft, roller valve lifters and a higher compression ratio. Speed sensitive steering was introduced on the trucks in 1997 along with a passenger side airbag. 1998 saw a revision to the steering wheel and airbag system and also the addition of the PASSLOCK II anti-theft system.

Engines:

Engine	Years	Power	Torque	Notes
4.3 L V6	1988–92	160 hp (120 kW)	235 lb·ft (319 N·m)
4.3 L V6	1993–95	165 hp (123 kW)	235 lb·ft (319 N·m)
4.3 L V6	1996–98	200 hp (150 kW)	260 lb·ft (350 N·m)
5.0 L V8	1988–95	170 hp (130 kW)	270 lb·ft (370 N·m)
5.0 L V8	1996–99	230 hp (170 kW)	290 lb·ft (390 N·m)
5.7 L V8	1988–95	210 hp (160 kW)	300 lb·ft (410 N·m)
5.7 L V8	1996	250 hp (190 kW)	330 lb·ft (450 N·m)
5.7 L V8	1997–99	255 hp (190 kW)	330 lb·ft (450 N·m)
6.2 L V8 Diesel	1991	130 hp (97 kW)	240 lb·ft (330 N·m)
6.2 L V8 Diesel	1992–93	143 hp (107 kW)	257 lb·ft (348 N·m)
6.5 L V8 Diesel	1994–99	180 hp (130 kW)	360 lb·ft (490 N·m)
7.4 L V8	1996-00	290 hp (220 kW)	440 lb·ft (600 N·m)	RPO L29
7.4 L V8	1990	230 hp (170 kW)	385 lb·ft (522 N·m)	454 SS Option
7.4 L V8	1991-93	255 hp (190 kW)	405 lb·ft (549 N·m)	454 SS Option

1996 GMC K1500 Sierra

Mid-cycle refreshes

This refresh occurred over several model years.

1994 C/K's received a new front fascia, federally-mandated CHMSL, many new exterior colors including a new two-tone option on the rocker panels, and new tire and wheel combinations.

1995 C/K's received a new interior that included a new steering wheel containing a drivers side airbag, a new dashboard containing a more central-mounted radio, dial operated HVAC system and an improved gauge cluster. New front door panels, and new seating were also included. The only interior bits not redesigned were the interior panels rear of the doors. Exterior changes this year included a special two tone faded paint job, available in many different varieties new gloss black folding exterior mirrors, and the door handles were changed from a smooth gloss black finish to a textured, satin finish.

In 1996, a passenger side mounted 3rd door was optional on extended cab models. A new range of engines were included. The "Vortec" engines meant HP increases across gasoline V6 and V8 smallblock engines.

1997 saw a passenger-side airbag on some models in order to comply with new federal regulations for light trucks. 2500 and 3500 models are exempt. This meant a slight dashboard redesign to incorporate these airbags. On models where passenger airbags weren't included, the space was occupied by a storage compartment.

1998 meant minor trim and badge updates as GM readied the end of the GMT-400 Platform. There was some overlap in 1999-2002 model years. In response to continued fleet sales the GMT400 trucks were produced as the Sierra Classic/Silverado Classic until the GMT400 ended production at the end of the 2002 model year. A Brazilian version of the GMT400 is currently produced in Brazil powered with a Chevrolet inline six.

The GMT400 and G-Van were the last two platforms to utilize the traditional small-block Chevrolet V8 in the 2002 model year.

The GMT800 platform was introduced in 1999 as the Silverado/Sierra.

454 SS

In 1990, Chevrolet introduced a high performance variant of the GMT400 under the Super Sport emblem called the 454SS. It was available only as a 2WD half-ton regular cab short box in Only Black only with a garnet red interior. The 454SS was powered by a 454 cu in (7.4 L) V8 producing 230 hp (172 kW) and 385 lb·ft (522 N·m). A 3-speed automatic transmission (Turbo Hydra-Matic 400) and 3.73 rear axle ratio added to the truck's performance. The axle itself is unique, being a 14bolt semi-floating unit which uses standard Chevrolet 5 on 5" wheels--the only factory produced 14 bolt axle with such a wheel bolt pattern. The suspension was also upgraded with 32 mm (1.3 in) Bilstein gas-filled shock absorbers, a 32 mm (1.3 in) front stabilizer bar, and 12.7:1 fast-ratio steering gear assembly.

Unique exterior features included a front air dam with fog lights, special rims, decals displaying "454SS" on the bed sides, red trim emblems, and black painted grille, bumpers, and mirrors. The interior was also unique with a special plush Garnet Red cloth with black trim, high-back reclining sport bucket seats, and center console.

For 1991, a four-speed electronic automatic transmission (known as the 4L80E), 25 more horsepower, and even higher torque (405 lbs/ft at 2400 rpm) were added to the 454SS. The rear-axle ratio was also lowered to 4.10:1 for extra jolt off the line. On the dash was a tachometer, oddly omitted from 1990 models.

The MSRP of the 1990 model was US$18,295 with a $550 destination charge. A total of 16,953 units were sold over the 4 years the 454SS was in production, with 1990, the first year of production, selling 13,748 units alone. The 454SS was discontinued after the 1993 model year.

In 1992-1993 other color options included Summit White and Victory Red, with multiple interior colour options. The rear quarter panel and tailgate decals also changed in 1992 to a more 'stylized' 'SS' and the Chevrolet sticker on the tailgate became much smaller and located on the corner area.

• 

  Chevrolet 454SS

• 

  1988–1989 Chevrolet C/K 1500 regular cab

• 

  1988–1993 Chevrolet C/K conversion

• 

  c. 1995–2000 K-Series brush truck near Tallahassee, Florida

• 

  1988–1989 Chevrolet C/K regular cab

• 

  1995-2000 Chevrolet C/K regular cab

• 

  GMC C/K Sierra regular cab

• 

  Chevrolet K2500 6.5 TurboDiesel with NV4500 Transmission

• 

  Chevy K3500 Crew Cab "Dually"

C3500 HD

GMC 3500HD Cab and Chassis with Dump Body

In 1991 GM introduced a 15,000 pound GVWR truck C3500 HD under the Chevrolet and GMC nameplates that was replaced by the 4500. It was marketed as a truck to bridge the gap between light duty trucks "pickup trucks" and medium duty trucks. The C3500 HD was only offered as a standard chassis cab until 1996 when a crew chassis cab was also offered. It is not clear if the crew cab was for fleet orders only, or if anyone could order it. An extended cab was never offered on the C3500 HD, though several have been custom made by the registered owners. All paint colors and all but the most deluxe cab options were offered in the C3500 HD. Upper cab marker/clearance lights were not optional equipment on the C 3500HD. The two mirror options are the camper style and west coast style mirrors.

The common drive axle used on the C3500 HD was the Dana 80, an 85.8" wide full floating axle with an 11 inch ring gear fitted with 19.5" x 6.0 tires. The front axle was a solid I-beam drop axle, similar to the axles of medium and heavy duty trucks. Both front and rear leaf sprung axles had disc brakes.

Available wheelbases were; 135.5", 159.5", and 183.5". The C3500 HD frames are very different from the C/K3500 cab and chassis. The C/K3500 cab and chassis and C3500 HD rear frame rails are spaced at industry standard 34" for easy fitment of bodies but that is where the similarity ends. The HD frame is much heavier and exits straight out behind the high mounted cab necessitating the unmistakable HD filler panel between the bumper and grille. The front fenders were also equipped with the same flares used on 4x4 models of the lighter trucks to cover the increased track width and larger tires.

Two transmissions were offered in the C3500 HD; the 4L80E 4-speed OD automatic, and the NV4500 5-speed manual.

GM never offered a four wheel drive counterpart of the C3500 HD, so there was no K3500 HD. Several aftermarket conversion companies offered a 4x4 version with either a Dana 60 or Dana 70 front axle. At least one company, Monroe Truck, was offered by GM dealers as a ship-through 4WD upfit using the RPO code VCB. Tulsa is another company that did 4x4 conversions for utility companies. Quigley conversions were mostly for fire/ambulance applications.

Engines 1991–2000

Engine offerings for the C3500 HD included three gasoline engines; from 1991-1995 5.7L 350 Small Block and 7.4L GEN V Big Block. In 1996 both the 5.7 and GEN V 7.4 were replaced by the new Gen VI 7.4L Vortec Big Block. The RPOL65 6.5L Turbo Diesel debuted in the C3500 HD in 1992, the year of the engine's release. The 6.5 was the only diesel engine offered for the entire production run of the T400 C3500 HD. No diesel was available for 1991, the first C3500 HD production year.

Engines 2001–2002

While all other C/K pickup models were dropped by 2000, the C3500 HD was produced until 2002 due to fleet demand. In the brochures it is referred to as Sierra Classic/Silverado Classic. There were two engine choices; The 8.1L Vortec Big Block replaced the Gen VI 7.4L Vortec Big Block and the venerable 6.5L Turbo Diesel.

Brazilian versions

A variant of the C/K family was introduced in Brazil during the 1960s. These used the instrument cluster from the 1960-66 US Chevrolet C/K series although the exterior sheet metal layout is exclusive to Brazil. The models built included a light truck, named C-10, and a SUV named Veraneio (initially known simply as Chevrolet C-14/16), introduced in 1964. They were initially powered with a Chevrolet 4.2 l (260 cu in) inline six based on the pre-1962 "Stovebolt" engines. Later they used the 4.1 l (250 cu in) engine from the Chevrolet Opala. In later years a four-cylinder diesel (Perkins Q20B) was also offered labeled as D-10 (light truck only). An ethanol-powered version of the C-10 was offered beginning in the 1981, dubbed the A-10.

After 1985, a redesigned pickup similar to the U.S. 1973-87 C/K truck was introduced as the C-20, powered with the 4.1 l (250 cu in) inline six of the U.S. Chevy II/Nova. Diesel and ethanol versions were also sold, labeled as D-20 and A-20 respectively (later models of the D-20 replaced the Perkins Q20B with a Maxion S4). The original version of the Veraneio was kept in production until 1988 (model year 1989), but it was eventually replaced with an updated version based on the C-20 family.

In 1997 GM introduced in Brazil the Silverado pickup with the same style of the 1988 American pickup. It was made until 2001. The line included an SUV named Grand Blazer. The 4.1 L (250 cu in) inline six engine with 138 hp (103 kW) was offered on both models with option for a MWM 4.2 L (260 cu in) turbo diesel engine producing 168 hp (125 kW). But the model earned a reputation for being a less capable work vehicle than its predecessor. After the Silverado was discontinued, GM ceased offering any trucks in this sector in Brazil.

See also

• Chevrolet Silverado / GMC Sierra
• Chevrolet S-10 / GMC Sonoma

External links

• The scandal of punitive damages. Titled: "The Most Dangerous Vehicle On the Road", Wall Street Journal, February 9, 1993, By Walter Olson