Third generation 1973–1987Third generation
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Also calledChevrolet Scottsdale
Chevrolet Custom DeluxeProduction1973–1987AssemblyAtlanta, 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)Engine250 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 V8Transmission3-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 manualWheelbase117.5 in (2,985 mm)
131.5 in (3,340 mm)
164.5 in (4,178 mm)Length188.5"(1971), 191.5"(1975), 211.8"[2]
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Facelifted GMC C/K
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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.[3] 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.[4] As a result, the third generation trucks are officially known as the "Rounded-Line" generation.[5][6][7][8] 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.[9] 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.[5][10][11]
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.[12]
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.[13] 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 could be purchased, along with a CB radio.[14]
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.
[edit] 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.[3]
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.[12] 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.[15]
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.[16] 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.[17] A Delco AM/FM audio sound system and a all-season climate control system that heated, cooled, cleaned, and dehumidified were optional extras.[18]
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.[3][19][20]
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.[21] 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.[22][23]
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.[3][16][24][25]
[edit] 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.[10][26][27] 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.[3] Engines choices initially consisted of six or eight cylinder engines with either manual or Turbo Hydra-Matic transmissions.[3]
C-Series pickups included two-wheel drive and featured a 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.[10]
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.[28] 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).[29]
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.[29]
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.[30] The Eaton ADL featured intelligent differential control via a 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.[31]
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.[32] 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.[32] 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.[12][33]
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.
[edit] 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.[16][34] 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.[16] Mechanical updates included more anti-corrosion techniques, reduced weight, and a new 5.0 liter 305 cubic inch V-8 with electronic spark control. The 5.7 liter 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 liter 305 engine with electronic spark control, which did not meet California's emissions requirements.[16]
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.[35] 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[36] 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.[37] The most expensive radio was the AM/FM stereo seek/scan with cassette tape at $594.[37] A variation of the C/K series was introduced in 1985 in Brazil,[38] replacing the locally-produced C10, introduced in 1964.
[edit] 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.[39] The name change is also found in the vehicle identification number.[40] 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.[41]
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.[42] The 5.7 liter 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.[43]
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.[44]
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.[45] 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.[46] It was also revealed that the Dateline report was dishonest about the fuel tanks rupturing and the alleged 30 mph (48 kph) speed at which the collision was conducted. The actual speed was found to be higher, around 40 mph (64 kph), 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.[47][48] GM filed suit over NBC's false report, with the broadcaster settling the same day.[49]
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.[50] 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.[51] 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.[52]
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.[52] 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.[52] 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.[52]
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.
Also calledChevrolet Scottsdale
Chevrolet Custom DeluxeProduction1973–1987AssemblyAtlanta, 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)Engine250 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 V8Transmission3-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 manualWheelbase117.5 in (2,985 mm)
131.5 in (3,340 mm)
164.5 in (4,178 mm)Length188.5"(1971), 191.5"(1975), 211.8"[2]
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.[3] 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.[4] As a result, the third generation trucks are officially known as the "Rounded-Line" generation.[5][6][7][8] 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.[9] 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.[5][10][11]
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.[12]
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.[13] 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 could be purchased, along with a CB radio.[14]
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.
[edit] 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.[3]
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.[12] 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.[15]
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.[16] 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.[17] A Delco AM/FM audio sound system and a all-season climate control system that heated, cooled, cleaned, and dehumidified were optional extras.[18]
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.[3][19][20]
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.[21] 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.[22][23]
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.[3][16][24][25]
[edit] 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.[10][26][27] 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.[3] Engines choices initially consisted of six or eight cylinder engines with either manual or Turbo Hydra-Matic transmissions.[3]
C-Series pickups included two-wheel drive and featured a 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.[10]
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.[28] 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).[29]
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.[29]
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.[30] The Eaton ADL featured intelligent differential control via a 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.[31]
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.[32] 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.[32] 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.[12][33]
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.
[edit] 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.[16][34] 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.[16] Mechanical updates included more anti-corrosion techniques, reduced weight, and a new 5.0 liter 305 cubic inch V-8 with electronic spark control. The 5.7 liter 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 liter 305 engine with electronic spark control, which did not meet California's emissions requirements.[16]
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.[35] 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[36] 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.[37] The most expensive radio was the AM/FM stereo seek/scan with cassette tape at $594.[37] A variation of the C/K series was introduced in 1985 in Brazil,[38] replacing the locally-produced C10, introduced in 1964.
[edit] 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.[39] The name change is also found in the vehicle identification number.[40] 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.[41]
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.[42] The 5.7 liter 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.[43]
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.[44]
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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
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.[45] 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.[46] It was also revealed that the Dateline report was dishonest about the fuel tanks rupturing and the alleged 30 mph (48 kph) speed at which the collision was conducted. The actual speed was found to be higher, around 40 mph (64 kph), 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.[47][48] GM filed suit over NBC's false report, with the broadcaster settling the same day.[49]
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.[50] 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.[51] 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.[52]
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.[52] 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.[52] 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.[52]
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.
