GM J platform
Encyclopedia
The J platform, or J-body, was General Motors' inexpensive front-wheel drive
Front-wheel drive
Front-wheel drive is a form of engine/transmission layout used in motor vehicles, where the engine drives the front wheels only. Most modern front-wheel drive vehicles feature a transverse engine, rather than the conventional longitudinal engine arrangement generally found in rear-wheel drive and...

 automobile platform
Automobile platform
An automobile platform is a shared set of common design, engineering, and production efforts, as well as major components over a number of outwardly distinct models and even types of automobiles, often from different, but related marques...

 from the 1980s and 1990s. The platform replaced the GM H platform
GM H platform (RWD)
The General Motors H platform or H-body is an automobile platform designation used for the 1971–1980 model year rear wheel drive line of subcompact cars...

. The J-platform is the only platform of GM to have a model in each of its "Original 5" passenger car divisions (Buick
Buick
Buick is a premium brand of General Motors . Buick models are sold in the United States, Canada, Mexico, China, Taiwan, and Israel, with China being its largest market. Buick holds the distinction as the oldest active American make...

, Cadillac
Cadillac
Cadillac is an American luxury vehicle marque owned by General Motors . Cadillac vehicles are sold in over 50 countries and territories, but mostly in North America. Cadillac is currently the second oldest American automobile manufacturer behind fellow GM marque Buick and is among the oldest...

, Chevrolet
Chevrolet
Chevrolet , also known as Chevy , is a brand of vehicle produced by General Motors Company . Founded by Louis Chevrolet and ousted GM founder William C. Durant on November 3, 1911, General Motors acquired Chevrolet in 1918...

, Oldsmobile
Oldsmobile
Oldsmobile was a brand of American automobile produced for most of its existence by General Motors. It was founded by Ransom E. Olds in 1897. In its 107-year history, it produced 35.2 million cars, including at least 14 million built at its Lansing, Michigan factory...

, and Pontiac
Pontiac
Pontiac was an automobile brand that was established in 1926 as a companion make for General Motors' Oakland. Quickly overtaking its parent in popularity, it supplanted the Oakland brand entirely by 1933 and, for most of its life, became a companion make for Chevrolet. Pontiac was sold in the...

). The first J-body cars were the Chevrolet Cavalier
Chevrolet Cavalier
The Chevrolet Cavalier was a compact automobile produced from 1982 to 2005 by General Motors. Built on the company's J platform, the Cavalier was one of the best-selling cars in the United States throughout its life.- Predecessors :...

, Pontiac J2000, and the Oldsmobile Firenza which entered production on March 23, 1981 as 1982 models. The Cavalier was phased out at the end of 2004 in favor of the new Chevrolet Cobalt
Chevrolet Cobalt
The Chevrolet Cobalt is a compact car introduced by Chevrolet in 2004 for the 2005 model year. The Cobalt replaced both the Cavalier and the Prizm as Chevrolet's compact car....

. The last surviving J-body car, the Mexican-built Pontiac Sunfire
Pontiac Sunfire
The Pontiac Sunfire was introduced for the 1995 model year as the compact car to replace the Sunbird. Not only was the name changed, but dramatic styling changes were included as well. The new styling was shared with the redesigned Chevrolet Cavalier...

, ended production in June 2005. There are three generations of the J-body: 1982 to 1987 (or until 1988 or 1989 depending on the model), 1988 to 1994, and 1995 to 2005.

Except for cosmetic differences, engine upgrades and the discontinuation of certain models, the platform remained largely unchanged throughout the years.

Design of the J-body dated back to the mid-1970s. At that time, GM-controlled divisions in different parts of the world manufactured totally different rear-wheel drive C-segment cars - the Chevrolet Vega
Chevrolet Vega
The Chevrolet Vega is a subcompact, two-door automobile that was produced by the Chevrolet division of General Motors for the 1971-1977 model years. Named after the star Vega, the car was powered by a lightweight aluminum-block inline four-cylinder engine...

 in America, the Vauxhall Cavalier
Vauxhall Cavalier
The Vauxhall Cavalier is a large family car sold primarily in the UK by Vauxhall Motors, the British division of General Motors , from 1975 to 1995...

/Opel Ascona
Opel Ascona
The Opel Ascona was a mid-sized car produced by Opel. It had three generations produced from 1970 to 1988. In motorsport, the Ascona 400 rally car driven by Walter Röhrl won the World Rally Championship drivers' title in the 1982 season....

 in Europe, the Holden Torana
Holden Torana
The Holden Torana is a car which was produced by General Motors–Holden's , the Australian subsidiary of General Motors from 1967 to 1980. The name comes from an Aboriginal word meaning "to fly". The first Torana appeared in 1967 and was a four-cylinder compact vehicle that had its origins in the...

 in Australia and the Isuzu Florian
Isuzu Florian
The Isuzu Florian was an intermediate car manufactured by Isuzu Motors Ltd. in Japan from 1967 to 1983. The Florian's body remained essentially the same through its unusually long life cycle, being afforded only two moderate facelifts...

 in Japan. Due to the exterior dimensions, and engines offered were found to be in compliance with Japanese regulations, the platform was classed in the favorable "compact" designation, and competed with other Japanese made products sold in Japan at the time.

It was decided that a common replacement would be developed to eliminate duplication of engineering effort and ensure parts interchangeability. When the Arab Oil Embargo forced CAFE mandates, and the fear of US$3.00 for a gallon of gasoline
Gasoline
Gasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...

, the J-body was practically produced straight off the drawing board.

On continental Europe, the car was sold as the Opel Ascona
Opel Ascona
The Opel Ascona was a mid-sized car produced by Opel. It had three generations produced from 1970 to 1988. In motorsport, the Ascona 400 rally car driven by Walter Röhrl won the World Rally Championship drivers' title in the 1982 season....

. In Britain, it was sold as the Vauxhall Cavalier. It was generally well received but was narrowly beaten to the European Car of the Year
European Car of the Year
The European Car of the Year award was established in 1964 by a collective of automobile magazines from different countries in Europe. The current organisers of the award are Auto , Autocar , Autopista , Autovisie , L'Automobile Magazine , Stern and Vi Bilägare .The voting jury consists of motoring...

 accolade by the Renault 9.

The fourth character in the Vehicle Identification Number
Vehicle identification number
A Vehicle Identification Number, commonly abbreviated to VIN, is a unique serial number used by the automotive industry to identify individual motor vehicles. VINs were first used in 1954...

 for a J-body car is "J".

Many vehicles used this platform including the following American nameplates:
  • 1982–1988 Cadillac Cimarron
    Cadillac Cimarron
    The Cadillac Cimarron was a compact car built by Cadillac based on the GM J platform. It was first introduced in 1981 for the 1982 model year, and sold through 1988. During its seven-year model run, 132,499 Cimarrons were built.-Development:...

  • 1982–1988 Oldsmobile Firenza
    Oldsmobile Firenza
    The Oldsmobile Firenza was a compact car produced by the Oldsmobile division of General Motors from 1982 to 1988. It was based on the front-wheel drive GM J platform, which was shared with the Buick Skyhawk, Cadillac Cimarron, Chevrolet Cavalier and Pontiac Sunbird...

  • 1982–1989 Buick Skyhawk
    Buick Skyhawk
    The Buick Skyhawk are automobiles produced by the Buick division of General Motors in two generations for the 1975 through 1989 model years. 1975 through 1980 models, all 2-door hatchbacks, were built on the subcompact, rear-wheel drive H-body platform...

  • 1982–2005 Chevrolet Cavalier
    Chevrolet Cavalier
    The Chevrolet Cavalier was a compact automobile produced from 1982 to 2005 by General Motors. Built on the company's J platform, the Cavalier was one of the best-selling cars in the United States throughout its life.- Predecessors :...

  • 1982 Pontiac J2000
  • 1983 Pontiac 2000
  • 1984 Pontiac 2000 Sunbird
    Pontiac Sunbird
    The Pontiac Sunbird, produced by the Pontiac division of General Motors, was Pontiac's second small-car offering of the 70's. The Sunbird model ran for 18 years and was then replaced in 1995 by the Pontiac Sunfire...

  • 1985–1994 Pontiac Sunbird
    Pontiac Sunbird
    The Pontiac Sunbird, produced by the Pontiac division of General Motors, was Pontiac's second small-car offering of the 70's. The Sunbird model ran for 18 years and was then replaced in 1995 by the Pontiac Sunfire...

  • 1995–2005 Pontiac Sunfire
    Pontiac Sunfire
    The Pontiac Sunfire was introduced for the 1995 model year as the compact car to replace the Sunbird. Not only was the name changed, but dramatic styling changes were included as well. The new styling was shared with the redesigned Chevrolet Cavalier...



International J-bodies include:
  • 1982–1988 Opel Ascona
    Opel Ascona
    The Opel Ascona was a mid-sized car produced by Opel. It had three generations produced from 1970 to 1988. In motorsport, the Ascona 400 rally car driven by Walter Röhrl won the World Rally Championship drivers' title in the 1982 season....

     C (Europe and South Africa)
  • 1982–1988 Vauxhall Cavalier Mk II (United Kingdom)
  • 1983–1989 Isuzu Aska
    Isuzu Aska
    The original Aska was developed as a part of GM's J-car program and was a welcome replacement for Isuzu's sorely dated Florian. Contrary to fellow J-cars from other GM divisions, the Aska only came in one body style, a 4-door sedan...

     (Japan) (originally called Florian Aska)
  • 1982–1989 Holden Camira
    Holden Camira
    The Holden Camira was a mid-size car produced by Holden, the Australian subsidiary of General Motors between 1982 and 1989. It was Holden's version of GM's J-body family of cars—GM's third "global" car platform....

     (Australia and New Zealand)
  • 1982–1996 Chevrolet Monza
    Chevrolet Monza
    The Chevrolet Monza is a subcompact, four-passenger automobile produced by the Chevrolet division of General Motors for the 1975–1980 model years. The Monza is based on the Chevrolet Vega, sharing its wheelbase, width and 140 CID inline-4 engine...

     (Brazil)
  • 1995–2000 Toyota Cavalier (Japan)
  • 1990–1997 Daewoo Espero
    Daewoo Espero
    The Daewoo Espero is a mid-size car produced by the South Korean company Daewoo Motors from 1990 to 1997. It was technically based on the GM J platform and had the distinction of a body designed by Bertone. It bore more than a passing resemblance to the Citroën Xantia, itself also a Bertone design...

     (South Korea)


Bodystyles included;
  • 2-door sedan - North America (until 1987), Brazil, Europe
  • 2-door coupé
    Coupé
    A coupé or coupe is a closed car body style , the precise definition of which varies from manufacturer to manufacturer, and over time...

     - North America (from 1988)
  • 4-door sedan - all markets
  • 3-door hatchback
    Hatchback
    A Hatchback is a car body style incorporating a shared passenger and cargo volume, with rearmost accessibility via a rear third or fifth door, typically a top-hinged liftgate—and features such as fold-down rear seats to enable flexibility within the shared passenger/cargo volume. As a two-box...

     - North America (until 1987)
  • 3-door hatchback - Brazil (NOTE: these are two different bodies, the Brazilian version had a more upright roofline than the USDM one)
  • 5-door hatchback - Europe
  • 5-door station wagon
    Station wagon
    A station wagon is a body style variant of a sedan/saloon with its roof extended rearward over a shared passenger/cargo volume with access at the back via a third or fifth door , instead of a trunk lid...

     - North America (until 1994), Australia (exported to the UK)
  • 2-door convertible
    Convertible
    A convertible is a type of automobile in which the roof can retract and fold away having windows which wind-down inside the doors, converting it from an enclosed to an open-air vehicle...

     - subcontracted to American Sunroof Corporation
    American Specialty Cars
    American Specialty Cars is an automobile supplier of highly engineered and designed roof systems, body systems and other specialty-vehicle systems for the world’s automakers...

     in North America and Baur
    Karosserie Baur
    Baur is a Karosserie or coachbuilder in Stuttgart, Germany, which has been building BMW convertibles since the 1930s. Currently, they are the body and assembly works for IVM Automotive, a member the Ed Group...

     in Europe; German market convertibles made by two different coachbuilders: Keinath
    Keinath
    Keinath Automobilbau is a car manufacturer based in Reutlingen, Germany owned and operated by Horst Keinath. The company began by producing a convertible variant of the Opel Monza, and the Vauxhall Cavalier Mark 2...

     and Hammond & Thiede. Brazilian convertibles made by Envemo and Sulam.
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