What You Need to Know About the 1986 Mitsubishi Montero
The 1986 Mitsubishi Montero arrived at a time when most trucks with four-wheel drive were built on body-on-frame pickup platforms with leaf springs and a two-speed part-time transfer case bolted on afterward. Mitsubishi took a different approach. They designed the Montero from the ground up as a dedicated four-wheel-drive vehicle, borrowing a lot of technical DNA from the Pajero/Shogun that was already selling in Japan and Europe. It came standard with full-time four-wheel drive, a three-mode center differential, independent front suspension, and a live rear axle on trailing arms. That combination was unusual for an American-market vehicle in 1986. The 1986 Montero was available with two engines in the US market. The gasoline option was the 2.6-liter 4G54 inline-four, making roughly 116 horsepower at 4500 RPM and 139 lb-ft of torque at 3000 RPM. It was not a fast engine by any measure, but it had reasonable low-end torque for its era and was known for lasting a long time if you changed the oil. The diesel was the 2.3-liter turbocharged 4D55, which produced about 85 horsepower and 135 lb-ft of torque. That diesel was torquey enough for crawling and towing light loads, and it got dramatically better fuel economy than the gas engine, though the trade-off was a loud, clattery idle and slower acceleration than anything else on the road. The transmission choices were a five-speed manual or a three-speed automatic. The five-speed is the one most people look for now. The three-speed automatic is adequate but can feel strained when the Montero is carrying passengers or going up steep grades at altitude.
The drivetrain is where the 1986 Montero gets interesting. It uses what Mitsubishi called Selective 4WD, a system with three selectable modes. In 2H mode, power goes only to the rear wheels and the center differential is free to allow front and rear axles to spin at different speeds, which is what you want on dry pavement. In 4H mode, the center differential locks, sending power evenly to both axles. This is for low-traction surface driving like dirt roads and snow. In 4L mode, the transfer case low range engages, doubling torque multiplication for technical terrain, rock crawling, and steep descents. The key practical detail most people miss: you can shift between 2H and 4H while driving without stopping, but you need to stop or move very slowly when shifting into or out of 4L. Attempting to engage 4L at speed will ruin the transfer case. The front suspension is independent with coil springs and a double-wishbone layout. The rear is a live axle located by trailing arms and coil springs. This setup gives the Montero solid articulation off-road, though not extreme by modern standards. The ride quality is better than a Jeep Cherokee or Bronco from the same era because of the independent front end, which also means better steering feel on pavement. The trade-off is that the front suspension components are not indestructible. Ball joints and tie rod ends wear out, and the upper control arm bushings are a common failure point if you're doing serious rock crawling. Ground clearance sits at around 8.2 inches with the standard suspension. The approach angle is approximately 34 degrees and the departure angle is about 26 degrees. These numbers are decent for moderate trails but not class-leading. If you plan to tackle anything beyond intermediate-level trails, you will want to lift it slightly or at minimum install bump stops that allow more droop.
I have owned and worked on several of these over the years. The most frustrating problem I encountered was with the center differential selector mechanism. The cable that operates the 4WD select switch from the dash to the transfer case can stretch and loosen over time. What happens is you turn the dial to 4H, but the transfer case does not actually engage. You drive around convinced you have four-wheel drive locked up, then wonder why you still get stuck in mud. The fix is to adjust the cable tension at the transfer case lever. There is an adjustment nut on the cable end, and with a few turns you can usually get proper engagement. If the cable is frayed internally, replacement is the only reliable solution, and the part is inexpensive, probably $25 to $35. Another issue that deserves mention is the transfer case itself. The 1986 model uses a chain-driven internal mechanism. These chains tend to stretch over high mileage, especially if the unit has not had regular fluid changes. The symptom is a rattle from the transfer case at idle, particularly noticeable when you let off the throttle. It sounds like marbles in a tin can. Fixing it requires removing the transfer case and replacing the chain and sprockets. It is a significant job but doable with basic tools. Avoid the temptation to just pour additives into the fluid and hope for the best. This is a mechanical wear issue, not a lubrication problem. The 2.6L 4G54 engine has a known weak spot with the timing belt. The water pump is driven by the timing belt, which means if the belt goes, the water pump fails, and the engine overheats almost immediately. Changing the timing belt should always include replacing the water pump, thermostat, and all associated tensioners. Doing this separately just delays the inevitable and costs more in labor. The recommended interval is 30,000 miles or two years, whichever comes first. Most owners ignore this and run the belts until they snap, which is a gamble.
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The diesel 4D55 has its own set of concerns. The turbocharger is a reliable component in most cases, but the intercooler piping can crack at the joins. Check the plastic tubing between the intercooler and the throttle body for splits and cracks. Also inspect the EGR cooler for carbon buildup, which can cause rough idling and loss of power. A simple test is to unplug the EGR valve connector and see if the engine runs smoother. If it does, the EGR system needs cleaning or the valve is stuck open. Body rust is a factor with these vehicles, though not as bad as some contemporaries. The most vulnerable areas are the wheel arches, the frame rails underneath, and the floor pans near the pedals. The Montero was not heavily used in salt-belt states like some domestic trucks, so rust is often less severe than you might expect. Still, a thorough undercarriage inspection is essential before buying any used example. Maintenance checklist for the 1986 Montero:
Transfer case fluid: change every 30,000 miles using 80W90 gear oil. Front and rear differentials: same interval and specification. Engine oil: 10W-30 for the gasoline engine, 15W-40 for the diesel under normal conditions. Brake fluid: flush every two years. The braking system uses a dual-circuit hydraulic layout with a combination valve that modulates rear brake pressure based on load. If the brakes feel spongy or uneven, inspect the combination valve for internal wear. It is a common source of brake problems that gets misdiagnosed as a master cylinder issue. When it comes to aftermarket support, the Montero is not as well covered as a Jeep Cherokee or a Ford Bronco. Parts availability has improved in recent years because the enthusiast community has kept these alive. Suspension components are available from companies like Old Man Emu andARB, which offer upgraded lift kits and shock absorbers. For off-road tires and wheels, any standard five-lug pattern works. The Montero uses a 5x114.3 bolt pattern with a center bore of 78.1mm. One thing to understand about buying a 1986 Montero today is that condition varies wildly. You will find examples with 80,000 miles that need a complete engine overhaul and examples with 200,000 miles that run perfectly. Mileage is not always the best indicator of health on these vehicles. The transfer case, the front driveline, and the suspension are what matter most. Ask the seller about how the 4WD system has been maintained and whether any work has been done on the differentials and transfer case recently. If the answer is vague, walk away.
The 1986 Montero is not the most powerful off-roader you can buy. It is not the most comfortable daily driver. It does not have the modern electronics and driver aids that newer vehicles offer. What it does have is a simple, mechanical drivetrain that is easy to understand, easy to work on, and easy to repair in the field. That is the defining characteristic of a true off-roader. The engineering is straightforward enough that you can learn it, and the parts are accessible enough that you can fix it without relying on a dealership. If you are looking for a first off-road vehicle that will teach you how four-wheel drive works without breaking the bank, the 1986 Montero is worth considering. Just budget for immediate maintenance regardless of what the seller claims about its condition. A fresh set of belts, fluids in every system, and new brake pads is a realistic starting point for any used example you bring home. The cost is usually between $800 and $1,200 depending on how much you do yourself. After that, you have a capable machine that can handle a wide range of trail conditions reliably.
