Jeep Comanche

The Jeep Comanche (designated MJ) is a pickup truck version of the Cherokee compact SUV that was produced from 1986 to 1992. Rear-wheel and four-wheel-drive models were available as well as two cargo box lengths of six and seven feet.

Unique structure
The Comanche is a monocoque (unibody) vehicle, an unusual form of truck design, like the Volkswagen Rabbit pickup and Dodge Rampage. Jeep designers based its body, styling, and suspension on the Cherokee, which had been introduced for the 1984 model year.

AMC's Jeep engineering staff designed a subframe that connected to the modified Cherokee unibody structure to support the cargo box. Two such subframes were designed; one for the long-bed model, which appeared first, and a second, shorter version for the short-bed, which debuted for 1987.

Suspension
The Comanche uses the Cherokee's front suspension, with coil springs and upper and lower control arms. The Cherokee and Comanche were the first Jeeps to use this new "Quadra-Link" suspension. It was argued that the coil springs allowed for greater ride comfort and axle articulation during off-road excursions. A trackbar is used to keep the axle centered under the truck. Modified versions of this same basic suspension system were later used on the Grand Cherokee and the TJ Wrangler.

For the rear suspension, the truck uses leaf springs that are considerably longer than on Cherokees, which give Comanches good load-carrying capacity. There is also a heavy duty "Big Ton" package available (known as the "Metric Ton" package outside the U.S.) for long-bed models. The package included heavier-duty leaf springs and wheels, larger tires and an upgraded rear axle to a Dana 44 instead of a Dana 35, which increases stock payload capacity from 1400 lb to 2205 lb, well above that of any other pickup of the Comanche's size. In fact, a Metric Ton Comanche's payload rating is higher than that of many larger pickups.

Drivetrain
Jeep offered the Comanche with a selection of engines, including the 4.0 L, 242 CID straight-6 engine found in many Jeeps from 1987-2006.

The inaugural 1986 Comanches could be equipped with one of three engines. The AMC 150 2.5 L, 150 CID I4, The General Motors LR2 2.8 L V6, or The Renault 2.1 L I4 turbo diesel were all offered from the start. The V6, which was the same basic unit used in the first generation Chevrolet S-10, had 7 hp less than the base four-cylinder, only slightly more torque, and was equipped with a two-barrel carburetor instead of the four-cylinder's electronic TBI fuel injection. In addition, fuel mileage with the V6, particularly in four-wheel drive models, was generally poor.

Changes to the engine lineup happened in the truck's second year on the market. For 1987, the 2.8 L V6 was replaced by the new fuel-injected 4.0 L, 242 CID AMC 242 inline-six that delivered 173 hp, 63 more hp than the V6. The new six-cylinder was also more fuel-efficient. The slow-selling turbodiesel was officially dropped at some point during the model year.

Other changes under the hood occurred in 1991, when Chrysler adopted their own engine control electronics to replace the original Renix (Renault/Bendix) systems. One positive effect of this change was that the 4.0 L, 242 CID, I-6 engine gained 17 hp (to 190 hp, having already gained 4 hp in 1988), while the 2.5 L, 150 CID, I4 engine jumped from 117 hp to 130 hp. In addition, most parts for the Chrysler systems are easier to come by, even though many Renix parts were borrowed from GM at the time, and are still widely available today and most are surprisingly cheap. Most people won't consider a Renix Comanche, as it has no Check Engine Light. (CEL) But if the owner can operate a simple and cheap multimeter, they will find that Renix systems are quite easy to diagnose and keep running.

During the production life of the Comanche, six different transmissions were offered, manufactured by Aisin, Chrysler and Peugeot. Aisin provided the AX-4 (four-speed), AX-5 and AX-15 (five-speed overdrive) manual transmissions, along with the AW-4 four-speed automatic that was used beginning in 1987. This is the same Warner transmission used in early to mid-nineties 4Runners with the 3.0 and some 22re 4wd. The AX-15 was phased in to replace the Peugeot BA-10/5 five-speed that had been used from 1987 until mid-1989 behind the 4.0 L I-6 engine.

The Comanche came equipped with a rather unique weight sensing rear brake proportioning valve. This valve has become a matter of massive contention and controversy in the MJ sphere. The proportioning valve is adjusted based on the weight in the bed. The more load in the bed the more fluid is diverted to the rear brakes. Many owners dislike the "big brother" qualities of the weight sensing valve and thus install the tried and true fixed proportioning valve.

Although Chrysler purchased AMC (and, by extension, Jeep) in 1987, only one Chrysler transmission was ever used in the Comanche, and that was prior to the takeover. 1986 models equipped with the 2.5 L I4 or 2.8 L V6 were offered with Chrysler's three-speed TorqueFlite A904 automatic. Throughout the Comanche's production run, Chrysler would continue AMC's practice of purchasing Aisin automatics that began in 1987.

Phaseout
After the Chrysler buyout, the Comanche, like the Cherokee, received only minor changes, primarily those that would improve reliability and parts interchangeability with other Chryslers. The lack of an extended cab body style, which all other compact trucks were offering by the time of the Comanche's debut, and the fact that the Comanche's prices were, in any given model year, higher than those of the top-selling American compacts (Ford Ranger and Chevrolet S-10), led to lagging sales as customers went elsewhere for roomier trucks.

As sales dropped, the Comanche was planned for discontinuation. In 1990 the National Council of Jeep/Eagle dealers asked Chrysler to discontinue the Comanche, and allow them to sell a version of the Dodge Dakota pickup.

The company chose to cancel the Comanche on June 12, 1992, after only a few thousand trucks had rolled off the Toledo, Ohio assembly line.

Body
The body comes only in standard size cab model (no extended cabs) with a rear fold down tailgate. Comes in longbed or shortbed two-tone versions. Longbed versions come with a larger gas tank than the shortbed. The gas tank is located in front of the axle on both longbed and shortbed models. The shortbed version was not available in 1986.

Interior:

Door panels are removable as stock. MJ bench seats and MJ bucket seats share a common floor bracket. MJ seats DO NOT have the same mounting brackets as XJ seats. Gauge cluster is removed by 4 screws. Gauge cluster during '86 have mechanical-powered gauges. On '87-'90 gauges, The speedometer uses a cable, but all gauges '91-'92 use a computer speed sensor in the transmission instead of a cable.

Wheelbase:

Short Bed 2wd=113.1 4wd=112.9 (18 gal tank) Long Bed 2wd=119.6 4wd=119.4 (16 gal [longbed] 23.5 gal [optional '86-'88; standard 1989+)

Dimensions:

Overall length is 179.3" for shortbeds, 194.0" for longbeds Overall curb height is 63.7" for 2wds, 64.7" for 4wds Track width is 57" with the 15x6 rims, 58" with the 15x7s Body width at the rear flares was 71.7" Length of inside of box at the floor is 73.7" sb and 88.5" lb Width of box at the floor is 55.3" for both sb and lb Width between wheel wells is 43.8" Box depth is 16.4"

Essentially from the driver's door post forward they are the same as the XJ.

Engines

 * 2.5L I-4 TBI (Throttle Body Fuel Injection) - 117 hp @ 5,000 rpm, 135 ft lbs @ 3,500 rpm - used in '86 and updated in '87-'90 to 121 hp and 141 ft lbs (2.5L I-4 became MPI in '91 and is rated for 130hp @ 5,250 rpm and 149 ft lbs @ 3,250 rpm).


 * GM 2.8L V6 - 110 hp @ 4,800 rpm, 145 ft lbs @ 2,400 rpm - used only in '86, same as the engine found in the S-10s and Blazers. This is commonly replaced with the GM Performance Parts "crate engine" 3.4L V6.


 * Italian VM 2.8L Turbo Diesel - 140 hp, 236 ft lbs - used in overseas MJs.


 * Renault 2.1L I-4 Turbo Diesel - 85 hp @ 3,750 rpm, 132 ft lbs @ 2,750 rpm used '86-'87.


 * 4.0L I-6 MPI "Power-Tech Six" - '87: 173 hp @ 4,500 rpm, 220 ft lbs @ 2,500 rpm, redline 5,000 rpm. '88-'90: 177 hp @ 4,500 rpm, 224 ft lbs @ 2,400 rpm, redline 5,000 rpm. These year 4.0Ls are commonly referred to as Renix powered.


 * 4.0L I-6 MPI "Power-Tech HO" (High Output) - '91-'92:  190 hp @ 4,750 rpm, 235 ft lbs @ 3,950 rpm, redline 5,250 rpm.

Transmission Info
Manual Transmissions


 * AX-4 4 speed manual - manufactured by Aisin-Warner - used '86-'92 with 2.5L I-4 only.


 * AX-5 5 speed manual - manufactured by Aisin-Warner - used '86-'92 with 2.5L I-4, 2.8L V6 ('86 only), 2.1L I-4 Turbo Diesel and 2.8L Turbo Diesel(export model).


 * BA-10/5 5 speed manual - manufactured by Peugeot - used '87- Mid '89 with 4.0L I-6.


 * AX-15 5 speed manual - manufactured by Aisin-Warner - used Late '89-'92 with 4.0L I-6. (Swappable into the 2.5L I-4 but the bellhousing will not fit the AX-5. There is a Dodge Dakota 2.5L I-4 bellhousing that will fit the AX-15)

Automatic Transmissions


 * Torqueflight 904 3 speed automatic - manufactured by Chrysler - used in 1986 models only with 2.5L I-4 and 2.8L V6. It shares a bellhousing pattern with the Chevrolet 2.8L V6 (AKA 60 degree GM) and Cadillac FWD engines made after '89.


 * AW4 4 speed automatic - manufactured by Aisin-Warner - used '87-'92 with 2.5L I-4 and 4.0L I-6. The bellhousing pattern is different between the 4.0L I-6 and 2.5L I-4, but the 4.0L I-6 pattern is the same as AMC V8s (it is NOT the same as any Dodge originally designed engine)

Transfer Cases
The transfer cases used are all chain driven with aluminum housings. NP stands for "New Process" which is the brand, if you will.


 * NP207 - "Command-Trac" part-time only - 2.61:1 ratio low range - used '86
 * NP231 - "Command-Trac" part-time only - 2.72:1 ratio low range - shift pattern 2H - 4H - N - 4L - used '87-'92
 * NP228 - "Select-Trac" part-time OR full-time - 2.6:1 ratio low range - used '86

Suspension
The Comanche used the Cherokee's front suspension, with coil springs and upper and lower control arms. The Cherokee and Comanche were the first Jeeps to use this new "Quadra-Link" suspension. Coil springs allowed for greater ride comfort and axle articulation during off-road excursions. A track bar is used to keep the axle centered under the truck. Modified versions of this same basic suspension system were later used on the Grand Cherokee and the TJ Wrangler.

For the rear suspension, the truck uses leaf springs that are considerably longer than on Cherokees, which give Comanches good load-carrying capacity and a smooth ride. There is also a heavy duty "Big Ton" package available (known as the "Metric Ton" package outside the U.S.) for long-bed models. The package includes heavier-duty leaf springs, heavy-duty shocks, heavy-duty coils, the larger of the available wheels and tires and an upgraded rear axle, which increases stock payload capacity from 1,400 pounds to 2,205 pounds, well above that of any other pickup of the Comanche's size. In fact, a Metric Ton Comanche's payload rating is higher than that of many larger pickups.

Driveshafts

 * Front Driveshaft - On '86-'87 MJs (NP207 t-case) the front shaft is a "GKN" style shaft. On '87-'92 MJs (NP231/242 t-case) the front is a "double cardan" two-piece driveshaft with a CV joint at the transfer case end.

On '86-'92 models, the yoke slides in and out of the transfer case (or transmission in the case of 2wds) and is lubricated by fluid from the t-case or trans. Pulling the rear driveshaft off an MJ will allow fluid to pour out of the t-case or transmission.
 * Rear Driveshaft - 2 types of rear driveshafts were used in MJs. Both were one-piece designs (as opposed to a 2-piece "slip" design like the front 'shaft) with standard u-joints at both ends and the slip yoke located on the output shaft of the transfer case. Some MJs had truly solid shafts, while others came with a "rubber-isolator" feature. This design incorporated an can-in-a-can design at the axle end of the driveshaft with a 1/4" thick band of rubber between them.

Axles
Front Axles:
 * Dana 30 high pinion - reverse cut - 27 spline, 1.16" diameter shafts, 7.13" ring gear - used '86-'92. All axles are vacuum disconnect, and have 5-260x u-joints (except the rare '86 models equipped with the NP-228 Select-trac transfercase which had non-CAD Dana 30s)

Rear Axles:
 * AMC-20 - 29 Spline, one piece axle shafts, 8.875" Ring Gear; Metric Ton axle in '86.
 * Dana 35 non c-clip - 27 spline, 1.18" diameter shafts, 7.58" ring gear, 2.62" axle tube - used '86-'89
 * Dana 35 c-clip - 27 spline, 1.18" diameter shafts, 7.58" ring gear, 2.62" axle tube - used '89-'92
 * Dana 44 non c-clip - 30 spline, 1.31" diameter shafts, 8.5" ring gear, 2.75" axle tube - used '87-'92 on some (not all) MJs equipped with towing-prep package and all MJs equipped with the Metric Ton package.

All rear axles are made of a spring under axle (SUA) design.

Gearing
3.07 - used with 4.0L I-6 engine / manual transmission.

3.31 - used with the rare "Fuel saver" package in '86.

3.55 - used with 4.0L I-6 engine / automatic transmission and with the 2.5L I-4 / 4 speed manual.

4.10 - used with 2.5L I-4 engine usually with 5 speed, also came with '86 Metric Ton models.

4.56 - rare but can be found on some older (~ '89 ~) models with 2.5L I-4 engine and auto transmission

Cooling Systems
Open style - any normal cooling system used today. Opposite of closed style described below.

Closed style - has no radiator cap and utilizes a pressure bottle. This style cooling system was used in '87-'90 MJs, but can be easily converted to open system with a '91 or newer radiator.

Airbags
No airbags during Comanche timeline.

Trim Levels
1986 - Custom, X, XLS 1987 - Base (SporTruck), Pioneer, Chief, Laredo 1988 - Base (SporTruck), Pioneer, Chief, Laredo, Eliminator 1989 - Base (SporTruck), Pioneer, Chief, Laredo, Eliminator 1990 - Base (SporTruck), Pioneer, Chief, Eliminator 1991 - Base (SporTruck), Pioneer, Eliminator 1992 - Base (SporTruck), Pioneer, Eliminator

Production Numbers
MJ (4x4 only) SWB/LWB 1986 - xxxxx/23,251 1987 - 6,199/6,685 1988 - 6,895/9,167 1989 - 5,354/5,021 1990 - 3,283/2,129 1991 - 5,188 (TOTAL) 1992 - 3,142 (TOTAL)

Comanches today
Some value the Comanche for its perceived durable drivetrain and uniqueness, and also in part because of its legacy as the "last Jeep pickup." Because of its rugged build and almost lifetime drivetrain in when equipped with the 4.0, the Comanche commands a premium much higher than many Jeeps of similar vintage.