Mitsubishi Triton Problems

This is another common question, but it’s one without a simple answer as the Triton’s transmission is not designed to have its fluid checked by the owner. As such, it has no dipstick, because Mitsubishi says the transmission is a sealed system and doesn’t need to have the level checked. Which is fine until the gearbox develops a leak and some fluid escapes. But that isn’t in the plan according to Mitsubishi.

The fluid is only supposed to be inspected when the transmission is serviced, which happens from underneath the vehicle. At that point, the transmission is drained of all its fluid and the specified amount replaced. Which is absolutely no help to you wishing to check the fluid level and condition as a (sensible) preventative maintenance measure.

Freezing the owner out of any potential home maintenance might be a great way to save money on the production line, but it doesn’t do much for those of us who like to keep an eye on our cars before niggles become problems.

Squeaking when a car’s suspension moves up and down is usually down to a couple of things. Either there’s wear in a ball-joint or suspension bush, or the bushes and joints are full of dry dust. Have you driven the Triton off-road in sand or dust recently? You might find that some dust has managed to work its way into the rubber bushings and is causing the noise.

At worst, you may have damage to something in the suspension that is placing a load where it shouldn’t or perhaps even rubbing where it shouldn’t. With the vehicle securely parked, you can climb underneath and have a friend use their body weight to bounce the vehicle on the spot. If you’re lucky, you might be able to pin-point the source of the squeak.

Let’s go back to basics here: Is there water in the reservoir? It might sound like a silly question, but many owners don’t think about routine maintenance like this, mainly because modern cars are so reliable in the first place.

If there is water in the reservoir, can you hear the washer pump motor when you hit the lever for the washers? If you can, then there could be a blockage in the line somewhere (it wouldn’t be the first time an insect or dust has blocked one of these tiny tubes). If you can’t hear the motor, the problem is most likely an electrical one and could be anything from a fried pump motor to a simple blown fuse.

Don’t be confused by the wipers working and the washers not; they’re two very separate systems.

If the engine is running well, but the car won’t move in gear when you take your foot off the clutch, it’s very likely that your clutch has failed. The clutch is responsible for transferring power from the engine to the gearbox and, if it wears out, it can no longer do so and the vehicle will just sit there and not move even when you take your foot off the clutch pedal and the car is in gear.

You noted that the car had previously seemed to lose power, but this was more likely to be the start of the clutch failing and not transferring all the power it should have been. Eventually, though, the failure became total and no power is getting through to the gearbox (and, therefore, the wheels).

A new clutch is the likely fix but make sure to check the flywheel for damage and wear while the car is apart.

There wasn’t a recall for this problem on this model, but there was a service bulletin (like a recall but for a non-safety related issue). The problem was the same as yours; examples of this diesel engine were overheating. The cause was deemed to be a loss of coolant and was related to poor cylinder-head gasket sealing. In turn, that was deemed to be the result of a too-rough metal surface on the cylinder block where it joined the cylinder head and sandwiched the gasket.

Mitsubishi introduced measures such as a different coolant concentration, a different radiator cap and an ECU that gave more warning to the driver. But none of these things actually fixed the issue with the head gasket and the metal surfaces. In fact, it wasn’t until 2014 production that Mitsubishi changed the machining process on the production line to give a smoother head-gasket sealing surface which solved the problem for good.

It seems that some engines had problems while other simply did not. Hard use such as towing heavy loads or driving at sustained high speeds made the problem more likely to surface.

From memory, this model Triton featured a dual-mass flywheel. These were fitted to smooth out the engine and make gear changes quieter and smoother. But when they fail, they can produce the sort of symptoms you’re hearing.

Instead of a one piece, solid flywheel, the dual-mass unit is made in two parts with flexible couplings between them. These couplings absorb some of the shock of gear-shifts and engine vibrations, but when they’re worn out, the whole assembly becomes `loose’ and starts producing clunks and bangs. Replacing the flywheel is the only fix, but make sure you replace the clutch assembly at the same time. Some companies also offer a single-piece flywheel conversion for this vehicle to prevent the problem occurring again.

Blow-by is a normal part of engine operation, particularly turbocharged engines where the combustion chamber pressures can be extremely high, forcing gasses past the piston rings and into the crankcase. Excess blow-by, however, suggests that there’s perhaps an overboost problem, wear in the engine or that the ventilation system designed into the emissions controls of the engine is not working properly.

The crankcase ventilation valve would be a good place to start checking as these can become very dirty and even clogged over time in a diesel engine, and a compression test of the engine might tell you more as well. The first thing to do is find another vehicle of the exact same make and model and see if it, too, has a similar level of blow-by in evidence. From there, you can decide which way to go, but either way, a good diesel mechanic should be able to identify the problem accurately.

What you’re probably hearing is the pump switching on to prime the engine’s fuel system so that it starts easily and promptly. Even though the engine isn’t running, when you switch the ignition on, systems like the fuel pump all come to life to get things ready to be started and driven. When the pump has generated enough fuel pressure and volume to start the engine, it can then switch off and only switch on again once the engine is running and a constant supply of fuel is required. This could be why it only runs for a few seconds when you first turn the ignition on.

This is pretty normal, but what isn’t is if the pump starts to make a new noise or the tone of its buzzing changes. At that point, what you might be hearing is wear or damage inside the pump.

This could be a differential problem or even something like a collapsed wheel bearing. But it’s most likely to be a seized brake or parking brake that is causing this problem. Has the vehicle been sitting around for a long time without moving? That’s a common way for brakes to seize and lock the wheel, preventing it from turning.

You might be able to knock the park brake free with a bit of persuasion, or maybe crack the bleed nipple on the brake itself to let the pressure off the brake and free it. But if the brake is rusted on, then you’ll need to disassemble it to bring it back to a condition where the vehicle is safe to drive again. Even if you get it moving again, a thorough disassembly and inspection is warranted to make sure it’s 100 per cent safe to go back on the road.

Like anything mechanical, the gear-shifting mechanism in a car can become slack, or sloppy, over time and kilometres. Play can develop in the linkages and levers that select each gear, or in the part where the gear-shift itself is joined to those selectors. Also, the actual selectors that disappear into the gearbox and physically shift the gears can also develop excess movement or play.

You can probably remove the shifter boot and centre console inside the cabin and check for looseness in the upper part of the shifter mechanism, but to check the whole thing, you’ll need to climb under the car and feel for play and look for broken clips, missing springs and worn out bushes. The good news is that it’s probably an external wear issue and not something inside the gearbox itself.