A squeak when taking off from rest could be anything from a brake problem to a wheel bearing fault, a noisy engine drive-belt, bent axle, a dry suspension bush, worn universal joint or just about a hundred other things, including the driveshaft you already suspect.

Of potentially greater concern is the cut-off exhaust system or, more correctly, the previous owner. Anybody who cuts up an exhaust to make more noise is also a likely candidate to have driven the vehicle hard. It might be better to find a vehicle that hasn’t been messed with and potentially abused.

A sawn-off exhaust system shouldn’t harm the turbocharger or engine, but it can make a difference to performance due to reduced back-pressure. It also makes me wonder what else has been changed of fiddled with in the name of more power. Sometimes the performance will actually be improved, but you also open a can of legal and insurance worms by changing things like factory exhaust systems in what is a fairly agricultural way.

A lot of modern transmissions don’t have a dipstick at all, particularly as manufacturers move towards transmissions that have very long service intervals and are considered sealed systems. Which is fine until it’s not. And that’s when you need to check the level and condition of the transmission fluid.

The good news is that the BT-50 in question does have a dipstick. The bad news is that’s mighty difficult to get to. You need to be under the car (so safety is the key here) and then locate a 19mm fitting on the driver’s side of the transmission. By unscrewing this fitting, you can withdraw the dipstick and check the level. The other catch is that you need to do this with the engine running (to get an accurate reading) and the dipstick is located close to what will therefore be a hot exhaust system.

All of this means it’s really a job for a specialist with a hoist and is a great example of a carmaker saving a few cents per car in production at the expense of the greater running costs for the owner over the life of the vehicle.

The fact that the fuel economy average seems to be creeping up can have a lot to do with the fact that you’re becoming more familiar with the vehicle and using more throttle as a result. But remember, too, that until you reset the average on the trip computer, what you’re seeing is the full history of your consumption from when the trip computer was last zeroed, not just the most recent trip you’ve done.

It's true that engines often start to use a little less fuel as they 'bed in’ after a few thousand kilometres. And for a modern turbo-diesel like yours, I reckon 10,000km or even 15,000km might be the magic number. However, don’t be too disappointed if it doesn’t come down a whole lot. I reckon for that vehicle, driven the way you’ve described, 10 or 11 litres per 100km isn’t a bad average to aim for.

Other factors play a big part, too. Does the vehicle have a bull-bar or roof racks? Both these add weight and aerodynamic drag respectively, and can easily make the car consume more fuel. A roof rack at 100km/h can be worth an extra litre per 100km.