Mitsubishi Pajero Sport Gearbox & Transmission Problems

This is not necessarily a problem, but rather a characteristic of modern, multi-ratio transmissions. They can give the impression that they’re constantly searching for the right gear for the conditions, and it’s worse in hilly country or if you’re towing something. By constantly trying to be in as high a gear as possible, the engine will theoretically use less fuel.

Probably the real question is why a computer-controlled turbo-diesel engine needs an eight-speed transmission in the first place. The answer is that it’s all to do with recording a better fuel consumption number than your opposition on the official test. Sometimes, the vehicle has more gears than it can actually use in Australia. Our 110km/h freeway speed limit meant that early examples of the Toyota LandCruiser 200 Series (which had `just’ six gears) wouldn’t shift into top gear. That’s because the factory calibration told the transmission it could only use sixth gear at speeds of more than 115km/h. Which, just wasn’t happening for the vast majority of 200 Series owners in this country. A reflash for the computer fixed the problem, allowing the Cruiser to select top gear at closer to 90km/h, but it’s a great example of where transmission tech is heading.

This type of problem can have any number of causes. The best option is to have the car scanned electronically to see what fault codes have been logged by the on-board computer.

You could be looking at a fuel issue, something purely mechanical (like the idle-speed set too low) a blocked air-filter, a computer issue or any number of sensors that are not playing ball. But until you interpret the fault codes, you’ll be flying blind and potentially replacing things that aren’t the cause of the stalling problem.

I’d certainly be taking the vehicle back to the workshop that serviced it and pointing out that the problem only occurred after they'd 'fixed' it.

By and large, a car should perform the same day in, day out without any huge (or even noticeable) changes in its performance. So I’d say, yes, something is wrong with your car. As for the cause, well, it could be anything from poor fuel to a faulty battery to a park-brake that is sticking on. It’s impossible to diagnose problems like this one remotely, so have it checked out at a workshop. Continuing to drive it with a fault is asking for more damage to be done.

You have a very common-sense approach to this Neil, and I agree with your theory 100 per cent. Towing a heavy load in an overdriven gear – whether it’s a manual or automatic gearbox – is not a great idea. Some gearboxes are obviously stronger than others, but even so, I reckon it’s just a good policy based on the principles of mechanical sympathy.

Towing in overdrive places huge stresses on the mechanical components of a gearbox – a piece of equipment that already has its back to the wall with 2.3 tonnes of caravan trying to drag it to a stop – and limiting the load and stresses by sticking with a ratio no higher than direct-drive (1:1) just makes sense. Think of it like your legs when riding a push-bike: Using a higher gear is fine until the driveline starts to load up, such as when climbing a hill (or towing a caravan in your car) at which point you need to shift to a lower gear to avoid your leg muscles exploding.

You’re right in suggesting that your car heads for the higher gears in a hurry to reduce fuel consumption, and this is one of those times when the manufacturer has placed the official fuel-consumption number on the windscreen sticker over common-sense. Not that Mitsubishi is the only offender (far from it) but it remains that the engine and gearbox have been calibrated for maximum fuel economy rather than maximum mechanical sympathy.

Ands let’s be honest, with a big caravan hitched up behind, no vehicle is going to record brilliant fuel consumption figures, is it?