Mitsubishi Triton Gearbox & Transmission 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.

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.

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.

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.

There are a lot of possibilities here. Either there’s a problem with the actual shifter for the transfer-case (that selects two or four-wheel-drive) or there might be something amiss inside the transfer-case itself. But before you try anything else, make sure that the transmission is in Neutral. Many vehicles will not shift into or out of four-wheel-drive while the transmission is in Drive or Reverse. So stick it in Neutral and see what happens.

From memory, the 4WD selector in your ute is a mechanical lever, not one of those newer rotary knobs. So at least you won’t be trying to overcome an electronic selection problem that occurs in these later versions.

If you had a loss of drive in every gear, the suspicion would be that the transmission is low on fluid or the torque converter is not working properly. But if it’s only reverse gear that is playing up, the chances are that the bands or clutch pack that locks the transmission into Reverse is allowing the gears inside the transmission to spin without actually transferring torque to the output shaft (and thence to the wheels).

That said, there could be other internal problems that could cause this, so a visit to a transmission specialist is the best advice. Don’t delay it either, as continuing to drive the vehicle in its current state could do more damage to the transmission.

The cable that drives the speedometer is a likely candidate for this in some cars, Aaron, but mainly older ones than your Triton. The cable will eventually run out of lubricant, at which point it can bind up and won’t turn smoothly (the cause of the hyperactive needle) while also making a dry squawking noise (the budgies). But, from memory, your car has an electronically-driven speedo, so the cause is more likely that the speedometer itself is worn out and causing internal friction (for the same set of symptoms).

There are three (generally speaking) things that can be causing this problem, Mark. You could have a problem with the clutch, the gear selectors or something internal in the gearbox itself. A worn or collapsed bearing or mangled gear cluster could cause this, but I’d expect other symptoms like horrendous noises and the refusal to select some gears at all, not just randomly. If you’re lucky, the cause could a simple mal-adjustment of the selector mechanism.

Meanwhile, you’ve told me you don’t think there’s anything wrong with the clutch but, to be honest, I’ve seen these same symptoms before on cars with worn out clutches. Sometimes the actuating fingers of the clutch break, other times there’s just too much wear for the clutch to function properly. Sometimes it’s as simple as a leak from the clutch’s hydraulic system or a stretched clutch cable. But either way, clutch problems can certainly cause this sort of grief.

Reverse can be hard to select because the clutch is not disengaging fully, so try this experiment: Turn the engine off and try to engage reverse. If it goes in easily every time and only baulks when the engine is running, that’s a classic case of a dying clutch.

It could be a number of things, and the only way to establish the cause of the light flashing is to have a mechanic check it.

It could be a worn synchro, but I would suspect it’s more likely to be a worn clutch. Have a mechanic check it for you.