2021 Mitsubishi Triton Pricing and Specs

The rule of thumb is that a transmission (or differential) noise that comes and goes at various speeds is not too much to worry about. It’s when the noise is constant that you have a major problem. All transmissions wear over time and kilometres, so it’s natural for a transmission to start making a bit of a whine now and then.

Generally, these noises are the result of wear in either the bearings or the meshing surfaces of the gears themselves. If the noise goes away after 80km/h you could just continue to drive the vehicle and keep a note if things change. But if the noise is getting progressively worse or it’s really loud and/or grinding, then you probably need to have the unit checked by a specialist.

The simplest answer is that the engine’s idle speed is set too low. I think these engines used a stepper motor to control the throttle at idle, and if this fails the engine will run with some throttle applied, but will stall at idle.

If that’s not the cause, you need to look a bit deeper into things like fuel pressure at idle and whether there’s some kind of problem with the fuel-injection system. It could even be something as simple as a dirty fuel or air filter. A good mechanic will know how to alter the idle speed to prevent this happening, although it may involve a new stepper-motor unit.

A dirty or clogged fuel filter will stop a modern turbo-diesel engine dead in its tracks. In fact, it’s one of the first things a switched-on mechanic will check on vehicles like yours. So if the mechanic has changed the filter and restored to car to full health, then I reckon he or she has probably nailed the cause and fixed it very simply and cheaply for you.

Let’s be honest; there are literally thousands of things that could go wrong that might make your vehicle stop. Modern cars are very complex things, but you need to have faith that sometimes, simple problems occur and can be fixed simply.