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Driving the 840-hp Demon

Durango SRT at the track

Widebody Challenger drive

Jeep Comanche (1986-1992):
The off-road pickup that made few compromises

The 1986-92 Jeep Comanche (MJ) was an innovative pickup truck with strong engines, high capacities, and optional four wheel drive — using a unibody structure (albeit with a “uniframe”).

1986 Jeep Comanche ad

The Comanche was based on the new Jeep Cherokee (“XJ”), and shared its powertrains — rear wheel drive or optional “Command-Trac” four wheel drive that could shift from two to four wheel drive, at any speed — then still unusual. The Comanche had a choice of six and seven foot beds.

AMC Comanche pickup

A clever designed suspension provided a high running ground clearance, without putting the body too far off the ground. Buyers could easily go off-road, without losing their ease of entry or handling. Despite a lower cabin than other compact pickups, it beat the Ford Ranger and Chevrolet S-10’s payloads. The curb weight was, with the shortbed, just about 3,000 pounds.

Powertrains

1986 Comanche buyers could choose between three engines: a four cylinder, a small diesel, and a troublesome, 1986-only GM 2.8 liter V6 that was prone to oil and head gasket leaks. The smaller gasoline engine, the most powerful four-cylinder engine of any compact pickup, came with standard fuel injection, unusual in domestics at the time.

1988 Jeeps

Bob Sheaves wrote that the “Peugeot diesel was advanced, a decent performer, and thrifty (as well as inexpensive); but the market, supposedly wanting just that, ignored it.” He wrote that their experience with the Peugeot diesel may have resulted in Jeep’s reluctance to use diesels later.

amc engines

Starting in 1987 the new AMC four-liter six cylinder engine replaced the GM V6; fast and relatively efficient, it was quite popular, taking half of sales. The 1986 Peugeot diesel was replaced by a 2.1 liter Renault diesel (based on the 2.0 liter Douvrin), which was dropped midyear due to lack of sales.

1989 jeep comanche

The 4.0 liter straight-six (I6) was rated at 173 hp when it arrived in 1987. It reached 177 hp by 1989, and hit 190 hp in 1991. That might not sound like much by 2017 standards, but compare it to:

The four liter engine, closely based on the successful 2.5 liter four-cylinder, made the Comanche’s acceleration faster than most cars, and its torque allowed 5,000 pounds to be towed.

1987 4.0

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). Peugeot’s BA-10/5 five-speed supplemented Aisin-Warner manuals from 1987 until mid-1989. The Chrysler Torqueflite automatic was used in 1986 only, followed by the AW-4 four-speed automatic — another unusual feature for the time. It’s somewhat ironic that the Chrysler transmission was dropped just before Chrysler bought AMC.

The Comanche was the first production pickup with unibody and a removable bed. It was created by connecting a subframe to the standard Cherokee chassis for the cargo box; the 1987 Comanche introduced a different subframe for the short-bed version.

quadra-link

The front suspension used coil springs, with upper and lower control arms and a track bar to keep the axle centered. Dubbed Link/Coil (later called Quadra-Link), it provided greater wheel travel when off-road, without giving up on-road ride or cornering. Major advantage of this live-axle suspension, later adapted to the Grand Cherokee and Wrangler, were light weight, a compact design, and good articulation.

For 1990, the standard shock absorbers were twin-tube hydraulic designs; the off-road shocks were monotubes with high pressure gas, with a larger (1.77”) bore.

Jeep 4 liter engine

Traditional leaf springs stayed in back; the maximum payload (reported as 2,205-2,240 pounds) was comparable to some full-sized pickups. To get there, Jeep added items including heavy-duty U-joints and propshaft, Dana 44 rear axle, and heavy duty brakes.

selec-trakAccording to Bob Sheaves, the semi-floating axles used in the metric ton package were a hybrid axle—they used a Dana 44 ring, pinion, and differential case with smaller wheel bearings and Dana 35C design wheel ends on the axle shafts.

Standard towing capacity was 1,400 pounds (1,475 pounds starting in 1987), using a Dana 35 or Chrysler axle.

Brakes were disc in front, drum in back. Wheels were fifteen inches. Steering was recirculating-ball.

Land speed record and racing

In late 1986, Jeep racers set a speed record at Bonneville, hitting just over 144 mph. A special prepared, two wheel drive 1987 Jeep Comanche, powered by a modified 4-liter fuel-injected straight-six, set nine United States and four international records in Bonneville time trials.

1986 Jeep Comanche Land Speed Record

Thanks to
Peter Lechtanski

Its record average speed of was 141.381 miles per hour, in a two-way dash over a one-mile measured course; its peak speed was 144.028 mph. See the Land Speed Record Jeep Comanche page.

Jeep Motorsports also campaigned Comanches in 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.

museum comanche

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).

Former AMC engineer Bob Sheaves wrote: “In 1992, the Dodge Dakota trucks won the Mickey Thompson Stadium Truck series 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 V6!”

Life of the Comanche

The main change to the Comanche was the switch to AMC’s own straight-six engines in its second year, 1987; the next largest was likely the switch to Chrysler electronics. However, there were more subtle changes, resulting largely from Chrysler’s acquisition of AMC in 1987; after that, components supplied by GM and Ford were replaced by Chrysler parts, where possible.

Jeep Comanche pickup profile

The 1989 Comanche gained an Eliminator model with a standard six, rear drive, and manual five-speed transmission; the next year, there was a 4x4 version. The Eliminator had a new eight-slot body-color grille, color-keyed fender flairs, silver-painted bumpers, and tape-stripes. Perhaps more important, the 1989 and later Comanches had an upgraded rear suspension, which increased the payload.

The 1991-92 Comanches replaced the 1986-90 Renix ignition systems and engine computers with Chrysler systems, for easier diagnostics. Two yellow rubber covers on the right side of the engine compartment can be removed so dealers can use the DRBII and Jeep adapter to get codes and do tests. (Codes might not be stored in the Renix system.)

Year 2.5 HP 2.5 Torque 4.0 HP 4.0 Torque
1988 121 @ 5000 141 @ 3500 177 @ 4500 224 @ 2500
1990 121 @ 5250 141 @ 3250 177 @ 4500 224 @ 2500
1992 130 @ 5250 149 @ 3250 190 @ 4750 225 @ 4000

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. One major reason for the 2.5’s power boost was a switch from throttle body injection to multiple port injection, which also smoothed the idle. Compression on the 4.0 dropped from 9.2:1 to 8.8:1.

Sample of gas mileage 1989   1992
2.5 RWD, 4-spd man. 22 / 25   21 / 23
2.5 automatic 4x4 18 / 23   n/a
4.0 manual 4x4 17 / 22   17 / 21
4.0 automatic (RWD/4x4) 16 / 21   15 / 19

The Comanche, Cherokee, and XJ Wagoneer shared an assembly line, so building more Comanches meant sacrificing highly-profitable Cherokee and Wagoneer production. With demand for the Cherokee only increasing, and greater incentives needed to move the Comanche, the decision to end the pickup was perhaps inevitable. It did not help the Jeep pickup to have the Dodge Dakota, made by the same company, competing in the same segment.

The Cherokee was a blockbuster success; the Comanche was likely the best pickup in its class, for most buyers, but it never really gained a following. Certainly, it never came close to the sales of the (less impressive) Chevy and Ford compact pickups.

1990 spec

Dimension Inches
Head room 39.4
Leg room 43.0
Shoulder and hip room 55.3
EPA cargo volume, c.f. 38.6 RWD
46.4 4x4
Fuel tank (gallons) 18.0 Short bed
23.5 Long bed

1992 powertrain combinations

1992 specs


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