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2018 Jeep Wrangler • 2019 Scrambler Pickup
We have divided up the Jeep line into “current Jeeps” (the ones they still make), Jeeps of the Past, and Jeeps by Year and Category (where you will find some of the vintage years). We also have concept cars and shows.
See our full list of Jeep concepts
Launched in 1999 on the Jeep Grand Cherokee, the Quadra-Trac II transfer case normally sent most power to the rear wheels. When a wheel lost traction, a gerotor pump increased hydraulic pressure on a multi-disc clutch pack, sending power to the front axle.
The pump used a rotor driven by the front drive shaft and the case by the rear drive shaft, increasing pressure to the clutch pack in proportion to their speed variation. Clutch discs were alternately splined to the front and rear drive shafts. Because Quadra-Trac II could immediately pressurize the clutch pack, it had a faster response than a normal viscous coupling. (Quadra-Trac II's low range had a 2.72:1 torque ratio and fully locked the center differential).
A similar pump was in the Vari-Lok differential, but power transfer was proportional to wheel speed difference rather than torque difference. By avoiding the need to pre-load the differential, which causes wear in normal use, Vari-Lok could be virtually wear-free. Vari-Lok differentials were faster and smoother than viscous systems, and the response could be tuned to driving conditions, so it could be used in both front and rear axles.
In 1963, at Kaiser-Jeep, the influential Wagoneer was launched. In 1974, AMC would build the lower-cost Cherokee version of it; and when the Cherokee finally got its own body, Jeep sales would double.
AMC launched a key engine in 1964: the “Typhoon” 232 six, which would spawn the AMC Jeep 4.0 and 4.2 liter straight sixes, still competitive in the 1990s.
In 1970, AMC bought Jeep from Kaiser, which had never been able to achieve the sales needed for profits and regular product investments. Jeeps were already using AMC engines when AMC inherited the Gladiator pickup, Wagoneer, Jeepster Commando, and CJ-5.
During 1970, AMC worked on the Jeep line’s future, resulting in almost immediate changes — generally improvements; the purchase proved to be extremely fortunate for Jeep, which picked up a slow-selling but unique and high reputable truck/SUV line just as that segment was to soar. AMC also pared the Jeep line from slow-selling 38 models to 22 for the 1971 model year, cutting costs and allowing more investment in new models.
In 1972, Jeep Gladiator pickups became the J-thousand series. CJ-5 now had the 304 optional as well. The trusted but obsolete Willys four and six cylinder engines were phased out, and the 115-hp AMC 258ci six (4.2 liters) was phased in along with AMC V8s topped off by the 195-hp, 360 cid powerplant.
All lines disposed of the old Borg Warner auto (which dated back to the 1950s) and took on the B-W T10 4-speed with the Chrysler 727 "Torque Command" 3-speed auto or, for six cylinder engines, the 904 TorqueFlite (some 304s may have received 998 transmissions).
The next year, 1973, the Renegade package became very popular on CJs. Pickups were called simply Trucks, with Thriftside and Townside versions (single and double wall beds). The new Quadra-Trac system was launched, providing a modern full time four-wheel drive setup that let each wheel travel at a different speed, eliminating the “tire scrub” endemic to older 4x4 systems. New appearance packages were introduced to increase the Jeep line’s appeal to nontraditional buyers — something Kaiser had tried to do since the end of the Korean War — and the instrument panel was color-coded, given international symbols, and supplemented by an ammeter and clock.
The most significant introduction for 1974 by far was the Jeep Cherokee, the first Jeep to have been engineered by AMC — most likely with work starting in 1970, soon after the purchase — though in essence it was a Wagoneer with the back doors carved out. The Cherokee, which replaced the Commando, would resonate with the public — helped by a much-reduced product lineup with just nine models, far more practical for marketing than the 38 left by Kaiser. 1974 Jeep line sales were more than double what they had been in 1970.
In 1975, with AMC moving fast, CJs and pickups got the Levi’s package as an option, and the pickups were now called J-10 and J-20 - these were trim packages, not wheelbases. Midway through the year, the popular Cherokee Chief option package was introduced, collecting popular Cherokee options together. See our 1975-76 Jeep section. Jeep finally passed 100,000 sales — nearly three times the sales of 1970, its first year at AMC. Modernizing, cosmetic surgery, repowering, and slashing the product line to make choices easier all worked together to make Jeep attractive to the general public in a way it had never been before — with QuadraTrac doing its part to make 4x4s more practical in daily life.
The pace continued in 1976. The elongated CJ-6 was dropped from the domestic market, replaced by the CJ7 - which was longer than the CJ-5 but shorter than the CJ-6. The CJ-7 would bring the CJ series to a larger market, practically doubling its sales, thanks to the use of a General Motors automatic transmission coupled to the Quadra-Trak four wheel drive system. Before the CJ-7, CJ owners had to know how to drive a stick. See our 1975-76 Jeep section.
For 1977, Cherokee, J-10, and CJs had the "Golden Eagle" trim package. Wagoneer got the luxurious "Limited" package, which made it the leather-clad Cadillac (or Imperial) of SUVs.
The 401-powered Jeep Wagoneer did not return for 1978, but Jeep still had an excellent year, with a whopping 168,000 sales.
The luxury Wagoneer Limited debuted in 1979, bringing a new thread to Jeep; and plans were moving ahead at the military division for a new, larger all-purpose military vehicle. The AMC engineers worked in the Jeep tradition to create a vehicle that could not be stopped. The name of it was as yet undetermined.
In 1980, Renault purchased 25% of AMC; the V-8 option was deleted from all vehicles, leaving the 2.5 four and 4.2 six as the only engine choices. Jeep CJ was given the Pontiac 2.5 liter four cylinder, making it the first American-made 4x4 to beat 20 mpg in EPA testing.
A new Jeep, the CJ-8 Scrambler became the only convertible pickup on the market in 1981 — and it stayed that way for a reason (low sales). The Hummer concept was in the testing stages.
The next year, 1982, Renault was allowed to purchase 49% of AMC stock; Frank Swygert wrote that Renault’s cash was needed because Jeep sales plummeted with the 1980s oil crisis. Unfortunately, because Renault was partly owned by the French government, and a foreign company was not allowed to have a major role in defense contractors (at that time), AMC had to sell AM General to complete the deal; LTV bought the defense division, causing problems when, years later, AM General licensed the "Hummer" name and cues, including the “Jeep grille,” to General Motors.
One largely forgotten part of AMC history was the use of a computer for the electronic feedback carburetor which could provide mechanics with diagnostic information.
1984 brought a revolution and perhaps the most popular sport utilities of all time, as the SportWagon Jeep Cherokee and Wagoneer replaced their larger predecessors. Though lighter and shorter (bumper to bumper), the new Jeep XJ had more passenger room than the old ones, which dated back to 1963. AMC fours and a carbureted GM 2.8 V-6 were the engine choices; they were hooked up to Selec-Trac or Command-Trac 4WD systems.
The old Jeep Cherokee added a rear-wheel-drive model, though it was in its last year. The old Wagoneer also remained, now called the Grand Wagoneer, with standard luxury items such as power windows and locks, leather, A/C, auto, V-8, tilt leather wheel, shag carpet, and woodgrain.
Another key moment for 1984: A pioneering deal was made with China to build the new Cherokee at a plant in Beijing, a partnership that would last for decades, but would eventually be terminated by Daimler in favor of building Mercedes cars in Beijing.
The Jeep Comanche pickup debuted in 1986: an off-road capable, yet light, compact truck. Light and fast, the unit-body pickup had a high capacity for its class, but could outrun many cars.
Jeep Motorsports campaigned Jeep Comanches in both offroad (SCORE) and paved road (SCCA) competition. Mike Leslie, Larry Maddox, Curt LeDuc and others campaigned the SCORE teams, and the Archer Brothers (Tommy and Bobby) campaigned the SCCA mini truck cars. Lee Hurley built all the engines for the factory Jeep teams, both the 4 cylinder and inline 6. The Jeep Comanche set a speed record at Bonneville of just over 144 mph.
A major change came to Jeep’s core line, as the historic Jeep CJ, which traced its design directly back to World War II, finally ceased production, in favor of a clean-sheet design: the Jeep Wrangler. It wore controversial square headlights, and was far more stable (with a tighter suspension that made the ride stiff and almost punishing), and had a more car-like interior. It was powered by the AMC 2.5 four cylinder and 4.2l engines. The 2.5 would survive into the 21st century, and the 4.2, in 4.0 liter form, survived all the way to 2006.
1987 was a fateful year for many reasons, the biggest being Chrysler’s purchase of AMC. In addition, the 258 was refined and equipped with fuel injection to become the Jeep “Power-Tech Six,” — the 4.0. It produced 173 hp and 220ft/lb torque, and replaced the slow [and arguably unreliable] GM 2.8 V-6 in Cherokee, Comanche and Wagoneer. Jeep J-series pickup production, minimal for years, was finally halted.
For more details, see our 1987-1989 Jeep page.
Comanche Eliminator models with the new six could run 0-60 mph in a respectable 9.5 seconds. A new 5-speed manual and 4-speed auto accompanied the new SUV efficiency leader.
In 1991, according to Frank Swygert: “The High-Output (H.O.) 4.0 engine appeared in 1991 with a revised control system and head design. The intake ports on the head were raised 1/8" to give a straighter shot into the cylinders. Along with computer program revisions, this added 13 hp to the engine, thus creating the 190 hp H.O. version that was used through 2002.
“The same basic engine design had been used since 1963. Many people have updated older 232 and 258 versions by bolting on the 1987 and later head and fuel injection system, as well as adding the 258 crank and rods to the larger bore 4.0L to create a 4.5L (standard 4.0 bore) high torque engine. Parts interchangeability is extremely good. In general, parts from a newer engine will bolt onto any of the older engines, with some exceptions.”
Related Jeep Wrangler pages
Inside the Wrangler
Variants and related...
The 2018 Jeep Wrangler JL: suspension • aluminum vs steel • open or fixed roof • pickup
body engineering • weight, strength, and safety • transmissions • engines
Chrysler 1904-2018 •
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