Why does my 2018 Mitsubishi Pajero automatic want to shift up when going at 110km/h?

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.