This is one of those questions where there are no hard and fast answers. The lifespan of pretty much any automotive engine will be determined far more by the way it’s been used and maintained than any rule of thumb being tossed around the industry.

Vehicles that do mainly highway kilometres tend to last longer since the engine is under less stress than one idling in traffic and then accelerating from every traffic light. The same goes for vehicles that have never had a tow-bar fitted versus one that has hauled a three-tonne trailer every day of its life.

Servicing plays a huge part, too, and a well maintained engine will always outlast one that has had skipped oil changes and other preventative maintenance. Overall, diesels used to live longer than their petrol equivalents, but the extent to which modern turbo-diesels are tuned to deliver power and torque means that’s not always the case these days.

Over the years, we’ve seen these Ranger engines fail at mileages as low as 100,000km, while others make it to 300,000 or even 400,000km while still in good health. Common engine problems to watch out for with this model Ranger engines include failed EGR coolers, contaminated and even blocked inlet tracts, worn turbochargers, DPF problems and failures, leaking and faulty fuel injectors and coolant leaks.

This is a strange one. If you had a post-2015 Ranger, the suspicion would be that the electric power-steering was playing silly games and turning the wheel to the left randomly. (Electric power-steering with the ability to move the wheel without driver input is the technology that has made driver aids such as lane-keeping assistance and self-parking possible.) If there’s a fault with the electric motor, the computer that controls it or the sensors that tell the system what’s what, then you can have a problem like this occur.

But Rangers built prior to this date had conventional hydraulic power-steering which, without driver input, should not be able to turn the steering at all. Except yours does.

Probably the most important piece of advice is not to drive the vehicle any farther until the problem is fixed. Obviously, having a steering system with a mind of its own is a potential source of disaster.

The actual problem could be do with the valving that controls the steering rack (and its power assistance) and a pressure imbalance between the right-hand and left-hand side of the steering rack could potentially cause this sort of problem. The valve that controls the speed-sensitive aspect of the steering is a likely culprit here as a faulty one can lead to uneven pressures within the steering rack.

If you want to be proactive, check that the power-steering fluid in the pump (under the bonnet) is at the correct level. Then, start the car with the transmission in Park and turn the steering wheel from full right to full left lock a couple of time. This should purge any air from the hydraulic fluid and restore balance to the system. But really, this is a potentially very serious problem and needs to be checked by a specialist.

Transmission problems are not unheard of in the Ranger and problems usually stem from either the oil-pump gears wearing or problems with the valve body. If caught early enough, sometimes these problems can be fixed without changing the entire transmission, but in your case, it sounds like the wear or damage was terminal.

If the transmission was to fail again in another 120,000km, would you spend another $6000 on a vehicle with 240,000km on its odometer? That’s the real question here, and given the price of second-hand dual-cab utes, maybe you would. The option would be to sell the vehicle now, using the brand-new transmission as a major selling point. If the thought of another transmission failure is keeping you awake at night, then that’s one option.

Also, talk to the workshop that fitted the new transmission and ask if the replacement unit was fitted with updated mechanical parts that are likely to reduce the chances of the same problem happening again. Often, the industry develops these improved bits and pieces as a reaction to common failures and faults. If the replacement unit is better than the original, maybe it’s worth persisting with.