The Jeep Comanche (1986-1992)
The Jeep Comanche (MJ) was an innovative compact pickup with strong engines, high capacities, and optional four wheel drive — using a unibody structure (albeit with a “uniframe,” pictured below). The Comanche was based on the unibody Cherokee/Wagoneer (XJ), using their optional Command-Trac four wheel drive system (base configurations were rear drive). It could shift on the fly from two to four wheel drive, at any speed. The Comanche had a standard six foot bed, with a seven foot long bed optional.
The new Cherokee/Wagoneer had been introduced in 1984, and was far ahead of its (few) body-on-frame competitors. It was shorter in length than the first-generation Cherokee, and was over a thousand pounds lighter, checking in at a svelte 3,100 pounds. From this remarkable vehicle, well ahead of its time and its competitors, came the Jeep Comanche pickup. It had a lower overall height and bed height than Chevy or Ford pickups — yet, it had more ground clearance.
The Comanche shared its assembly line, so building more Comanches meant sacrificing production of the highly-profitable Cherokee and Wagoneer. That, and competition with the Dodge Dakota — after Chrysler acquired AMC — are probably the main reasons why the Comanche was eventually dropped.
Land speed record and racing
In 1986, its second year on the market, a 1987 Jeep Comanche set a speed record at Bonneville of just over 144 mph. A special prepared, two wheel drive Comanche, powered by a modified 4-liter fuel-injected straight-six, set nine United States and four international records in Bonneville time trials. The highlight was its record average speed of 141.381 miles per hour, in a two-way dash over a one-mile measured course; its peak speed was 144.028 mph. (Thanks, Peter Lechtanski, for this section.) See the Land Speed Record Jeep Comanche page.
Jeep Motorsports also 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. Bob Salemi set an IHRA record with a 4-liter Comanche in September 2009, in HT/SA, with a 12.95 quarter mile at 100 mph (New England Dragway - thanks, Bob Sheaves).
Bob Sheaves also wrote: “In 1992, the Dodge Dakota trucks campaigned in the Mickey Thompson Stadium Truck series won the championship from Toyota by a wide margin. In reality, these two trucks were the previous year's Comanches with the Dakota sheet metal. The trusty race modified 4.0 Jeep engines were even used instead of the Chrysler 3.9 V6s!”
At its launch in 1986, buyers could choose between three engines: a diesel, the most powerful four-cylinder engine of any compact pickup, and a troublesome GM V6. Starting in 1987 the new four-liter six cylinder (standard on Eliminator models) replaced the GM V6, making the Comanche quick indeed. The 2.5 liter four cylinder came with standard fuel injection, unusual in domestic vehicles at the time (though soon to be common). The Peugeot diesel advertised at launch was quickly followed by a 2.1 liter Renault diesel (based on the 2.0 liter Douvrin), which was dropped midyear.
The 4.0 liter I6 was rated at 173 hp when it arrived in 1987; by 1990, it had 177 hp. At that time, the bigger GM 4.3 liter V6 only made 160 hp, the Ford 4.9L I6 (used in the F150 and Econoline) only made 145HP, the Ford 4.0 V6 made 155HP, the Chrysler 5.2L made 170HP, Jeep’s own AMC-era 360 V8 (with two-barrel carb) made 144HP, and the Nissan 3.0 V6 (used in the Pathfinder) made 153HP.
Evan Boberg, an AMC engineer, wrote in his book, Common Sense Not Required, that the Comanche earned a lower profit than the Cherokee and Wagoneer, so that in effect the company lost money when making Comanches, leading to its being dropped (along with its competing with the Dodge pickups). He also wrote, “The story I was told was [that] the executive in charge of the design of the Cherokee hated the AMC inline 6 cylinder engine (the 4.2 liter) and specifically designed the Cherokee so it would not fit. The Nash 2.5 liter engine was fitted with fuel injection and the General Motors 2.8 liter V6 with oil leaks were the original engine options.” The four liter engine had long been under construction at AMC, and was based closely on the successful 2.5 liter four-cylinder. Its horsepower made acceleration faster than most cars, and its torque allowed 5,000 pounds to be towed. Not for nothing was the Cherokee popular, for an SUV of that era, among the police.
Aisin-Warner, a joint venture between Aisin Seiki and Borg Warner in Japan, provided manual transmissions, including the AX-4 (four-speed), AX-5 (five-speed), and AX-15 (five-speed). A Peugeot BA-10/5 five-speed was used from 1987 until mid-1989 with the I-6. The Chrysler Torqueflite automatic was used in 1986 only, followed by the AW-4 four-speed automatic.
The Comanche used unit-body construction, unusual among pickups; it was the first production pickup with unibody and a removable bed. The Jeep pickup truck was created by connecting a subframe to the standard Cherokee chassis for the cargo box; a different subframe was designed for the 1987 short-bed version. The front suspension used coil springs and both upper and lower control arms, the Jeep Link/Coil suspension (later called Quadra-Link), which provided for greater wheel travel when off-road without giving up on-road ride or cornering. A trackbar kept the axle centered. The Quadra-Link suspension would later be used on the Grand Cherokee and Wrangler. A major advantage of this suspension was its very light weight.
In back, traditional leaf springs were used to increase cargo capacity, with a maximum metric ton long-bed version through 1990. The 2,205-pound or 2,240-pound (depending on sources) payload capacity was comparable to some full-sized pickups; to get there, Jeep added heavy-duty U-joints and propshaft, Dana 44 rear axle, and heavy duty brakes, among other items.
According to Bob Sheaves, Dana 44 axles used in the metric ton package were actually a hybrid axle-a semi floating design, they used a D44 ring, pinion, and differential case with smaller wheel bearings and D35C design wheel ends on the axle shafts, when compared to the earlier D44 used in the CJ. He noted that the Class 7 racing cars started out as metric-ton MJs.
Standard towing capacity was 1,400 pounds (1,475 pounds starting in 1987), using a Dana 35 or Chrysler axle.
Starting in 1991, the Comanche's engines used Chrysler engine computers, allowing for easier diagnostics; before that, Chrysler had to honor contracts with AMC's ignition system vendor, Renix. There are two yellow rubber covers on the right side of the engine compartment; dealers can use the DRBII and the Jeep adapter to get codes and do certain tests. (Codes might not be stored in the Renix system and would have to be regenerated while the adapter was connected, according to Rob Mayercik.) Both engines jumped up in power, the 2.5 liter going up 13 hp to 130 hp — which was 30 hp more than Chrysler's own 100-hp 2.5 liter four — and the 4.0 going up 13 hp to 190 hp, well above the Chrysler 3.8 liter V6, which until 1993 only produced 150 hp and 213 lb-ft of torque).