Introduction
The United States Military issued a request during the Second World War for a vehicle that was versatile and met specific specifications. The requirements included four-wheel drive, a weight of 1,300 pounds, an 80 inch wheelbase, a maximum tread of 47 inches, an engine torque of 85 pound-feet, and a minimum ground clearance of 6.25 inches. Additionally, the vehicle needed to be able to carry up to 600 pounds as well as have a cooling system to prevent overheating at low speeds. It was crucial for the design and construction of this vehicle to be completed within 49 days from the date of the request.
Both the company now recognized as Jeep and Ford embraced the challenge and crafted the inaugural Jeep, named the Willys MB, in 1941 (Fetherston). The introduction of the Willys MB marked the inception of the Civilian Jeep series, also referred to as the CJ series. The CJ series exerted influence over the present Wrangler Series, which includes the YJ, TJ, and JK. Lastly, JGMS or Jeep Government and Military Sales reintroduces a military Jeep with the Jeep J8. From the first Willys MB to the Jeep J8, numerous changes have occurred and improvements have been made to constantly enhance the Jeep Wrangler (Origin of the Term Jeep).
Primary Military Jeeps Willys MB were the preferred choice for the United States Army during World War II. The Bantam car company initially met all the required specifications and deadlines, but it was determined that Bantam couldn’t produce enough Jeeps. As a result, Willys was selected to manufacture the Jeeps and make any necessary modifications to Bantam’s designs (Doyle). These Jeeps were incredibly versatile and reliable, as described by journalist Ernie Pyle who said they were “faithful as a dog, strong as a mule, and agile as a goat.” Between 1941 and 1945, a total of 335,531 Willys MBs were produced and utilized in various Army operations (Discover Jeep History). Figure 1 showcases an original 1941 Willys MB (IFCAR 2007).
Even with Willys’ involvement, the production volume still fell short of the Army’s demands. Hence, Willys sought Ford Motor Company as a sub-contractor to manufacture more Jeeps. Ford successfully produced 281,578 Ford GPW Jeeps, which were essentially the same but featured the Ford logo on their tailgate (Doyle).
CJ Models
The CJ or Civilian Jeep was the first Jeep made for public use. It was produced from 1944 to 1986 by various ownership and manufacturers. Willys-Overland manufactured the CJ from 1944 to 1953, followed by Kaiser-Jeep from 1953 to 1970. American Motors Corporation took over from 1970 to 1987. The main models produced during these years were the CJ-2A, CJ-3A, CJ-5, CJ-7, and CJ-8 (Chilton’s Jeep CJ/Scrambler, 1971-86 Repair Manual). In Figure 2, there is an image of a Jeep CJ-5 model with its original V6 engine (Ziemnowicz, Christopher 2008).
The first full production Jeep, the CJ-2A or Willys-Overland CJ-2A, was manufactured from 1945 to 1949. It was primarily designed for farming use, aiming to replace horses on farms. It featured a T-90 three-speed manual transmission and was powered by a 134CID Flathead Inline 4 engine with 60 horsepower (Chilton’s Jeep CJ, 1945-70 Repair Manual). Since it was intended for farm use, there were various optional equipment available to meet different farm needs (Discover Jeep History).
CJ-3A
The CJ-3A, released in late 1949, was an upgraded version of the CJ-2A and remained in production until 1953. Improvements included a stronger 10 leaf suspension and a relocated driver seat. From 1951 to 1953, Willys-Overland introduced a Farm Jeep variant of the CJ-3A with additional options for increased durability and farm-friendliness. According to Chilton’s Jeep CJ, 1945-70 Repair Manual, a total of 131,843 CJ-3As were produced and sold between 1949 and 1953. Following Kaiser-Jeep’s takeover of the CJ series production, the CJ-5 was introduced in 1954.
The CJ-5 had a range of styles and options, making each one unique. It offered either a 3-speed or 4-speed manual transmission. There were six different engines available for the CJ-5, made by various companies. AMC produced three engines: the 232 cubic inch (3.8 liter) AMC Inline 6, the 258 cubic inch (4.2 liter) AMC Inline 6, and the 304 cubic inch (5.0 liter) AMC V8. In addition, there was also a 151 cubic inch (2.5 liter) Iron Duke Inline 4, a 225 cubic inch (3.7 liter) dauntless V6, and a 192 cubic inch (2.3 liter) Perkins Diesel Inline 4.
The CJ-5 had a wider wheelbase and larger body compared to other Jeeps. It held the record as the longest produced Jeep model and introduced special models (Chilton’s Jeep CJ, 1945-70 Repair Manual). The CJ-7, produced from 1976 to 1986, saw 379,299 units built. It featured a larger wheelbase to accommodate an automatic transmission. Multiple engine options were available for the CJ-7: the 2.5 liter AMC Inline 4, 2.5 liter GM Iron Duke Inline 4, 3.8 liter AMC Inline 6, 4.2 liter AMC Inline 6, 5.0 liter AMC V8, and the 2.4 liter Isuzu Diesel C240.
According to Chilton’s Jeep CJ/Scrambler, 1971-86 Repair Manual, these engines were paired with either a 5-speed, 4-speed, or 3-speed manual transmission or a 3-speed automatic transmission. The Jeep Wrangler (1987) marks the transition from CJ to Wrangler as the fourth generation of Jeeps. It replaced the Jeep CJ Models and introduced a more advanced off-road vehicle. Since then, there have been several iterations of the Wrangler including the YJ in 1987, TJ in 1997, and JK in 2007. It is important to note that both the Jeep Wrangler and the Jeep Company have been owned and manufactured by Chrysler since its release in 1987 according to Gunther.
The YJ Wrangler was introduced in 1987 and produced until 1996. It featured square headlights which were not used on later models. Customization options included a choice between a soft top and a hardtop. To enhance driving comfort, the YJ had a wider track and lower ride height compared to previous models. All three engines used for the YJ were manufactured by AMC or American Motor Company.
Initially, the YJ offered three engine options: the 2.5 liter AMC 150 Inline 4, the 4.2 liter AMC 258 Inline 6, and the most powerful and preferred choice, the 4.0 liter AMC 242 Inline 6. In terms of transmissions, there were five stock options available for the YJ. The Aisin AX-5 and TorqueFlite 904 were paired with the four-cylinder engines, while the Aisin AX-15, Peugeot BA-10, and TorqueFlite 999 were paired with the six-cylinder engines (Gunther). Throughout its production years, various trim levels were introduced for the YJ Wrangler. The Islander model was produced from 1988 to 1993, while the Renegade model was produced from 1991 to 1994.
The Islander package offered various features such as a 20 gallon fuel tank, body color flares and side steps, sunset graphics, floor carpeting, and a center console with cup holders. It also provided the option of choosing between full or half doors. On the other hand, the Renegade package was the most luxurious option available for the YJ models. It included everything that was in the Islander package except for the sunset graphics. Additionally, it came with larger tires, wider aluminum wheels, and a full-size spare tire. It also had off-road shocks, full carpeting, a secure glove box and center console, and a few other upgraded features (Gunther).
The YJ paved the way for the TJ Wrangler to be released in 1997, with a major change being the return of the round headlights from the CJ Models. The TJ came stock with various engine options, including the 2.5 liter AMC 150 Inline 4, 2.4 liter PowerTech Inline 4, and the 4.0 liter AMC 242/PowerTech Inline 6 Engines. Different transmissions were also available for these engines. In addition, the TJ had two special models: the Rubicon and the Unlimited. The Wrangler Rubicon, introduced in 2003, offered many extra features (Discover Jeep History).
The Rubicon model was enhanced with more robust front and rear axles, differential locks, bigger wheels and tires, and a lower range transfer case. In 2004, the Unlimited version was launched with an elongated body that provided extra storage room. The following year, Jeep merged the characteristics of the Rubicon with the extended body of the Unlimited to establish the Rubicon Unlimited model. Shifting to the JK series, Jeep introduced a completely redesigned Wrangler JK in 2007.
The JK Wrangler was available in both 2-door and 4-door styles. From 2007 to 2011, it featured the 3.8 Liter EGHV6 engine and could be paired with either the 4-speed Ultradrive 42RLE automatic transmission or the 6-speed Chrysler NSG370 manual transmission. Starting from the new 2012 models, the JK now comes equipped with the 3.6 Liter Pentastar V6 engine and can be coupled with either the 5-speed W5A580 automatic or the 6-speed Chrysler NSG370 manual transmission.
In conclusion, Jeep and Ford supplied the United States Military with the Willys MB in just 49 days. For over 70 years, Jeep has provided the world with a true American-made 4X4 Freedom machine (Doyle).
Beginning with the Willys MB, which was issued by the Military, Jeep has continuously evolved and enhanced its design. The CJ, YJ, and TJ models were all produced by Jeep, with each one incorporating improvements from the previous models to create the ultimate Jeep. These earlier models played a crucial role in the development of the current Jeep Wrangler JK model. In fact, the success of the JK model inspired Jeep Government and Military Sales to reintroduce the military jeep J8 to the global market. As the oldest brand in off-road vehicles and sports utility vehicles, Jeep is constantly striving to be the leader in its field (Discover Jeep History).
Works Cited
- BrokenSpere. A covered Willys MB/Ford GPW at the Wings over Wine Country 2007 air show atthe Charles M. Schulz – Sonoma County Airport in Sonoma County, California. 18 August2007. JPEG file.
- “Discover Jeep History. ” Jeep. com. Web. 1 Dec. 2011. http://www. jeep. com/en/history/.
- Doyle, David. “M38A1. COM – Military Jeep History… ” M38A1 Restoration Site. Web. 01 Dec. 2011. <http://www. m38a1. com/Resources/history. htm>.
- Freeman, Kerry A. Chilton’s Jeep CJ, 1945-70 Repair Manual. Radnor, PA: Chilton Book, 1997. Print. Freeman, Kerry A. Chilton’s Jeep CJ/Scrambler, 1971-86 Repair Manual.
- Radnor, PA: Chilton Book, 1994. Print. Fetherston, David. Jeep: [warhorse, Workhorse & Boulevard Cruiser]. Osceola, WI: Motor International, 1996. Print.
- Gunther, Martin. Chilton’s Jeep Wrangler/YJ 1987-95 Repair Manual. Radnor, PA: Chilton Book, 1995. Print.
- IFCAR. 2007-2009 Jeep Wrangler Unlimited photographed in Annapolis, Maryland, USA. 7 April2010. JPEG file.
- “Origin of the Term Jeep. ” Military Information HQ. Web. 03 Dec. 2011. <http://olive drab. com/od_mvg_www_jeeps_origin_term. php>.
- Ziemnowicz, Christopher. Jeep CJ-5 model with original V6 engine. Red open body. 21September 2008. JPEG file.
