But when milady explained how she arrived at such a name for the 1997 Holden Rodeo one-tonner, all new-improved-and-shiny-bright, it was startlingly logical; it’s the sound the engine makes.

Not all the time of course, but when cruising comfortably between 80 and 100 km/h, the Rodeo’s turbocharged diesel engine emits a constant `tonk-a, tonk-a, tonk-a...’

Which is probably not what the designers at Isuzu-GM had in mind when penning-up this new generation Rodeo, which is undeniably streets ahead of any previous model with new styling and a major upgrade of comfort/convenience items.

Sleeker, more car-like styling reduced its drag coefficient by 10 percent, improving fuel economy and lowering wind noise, while it lost its side window vents with the benefits of increased mirror visibility and, again, less wind noise.

Isuzu-GM claims interior noise levels in all models have been substantially reduced, with selected areas of the dash, floor, body panels and hood insulated to achieve much lower noise levels, and after a week in the Rodeo Space Cab LX I am inclined to agree. It is still no Statesman, but certainly much quieter than before.

But the most significant changes occurred inside the cabin, where the dash layout is more modern and functional -- the ergonomic layout of controls is excellent, the steering wheel is a four-spoke style with a thicker rim, and bucket seat-equipped 4x4s now have a floor mounted park brake lever.

More stylish than before, but Rodeo is still a hard worker.

For serious work, Rodeo’s 2.8 litre turbodiesel takes some beating.

The all-new interior is much more efficiently laid out.

Something of a `hose-out special’ with its vinyl floor mats (definitely preferable for a serious work-truck), the LX cab-chassis’ Space Cab layout is also ideal for its intended role, providing a secure lock-up storage area behind the seats.

Ride comfort is rather good, though the tail-end with its heavy-duty leaf springs is predictably keen to jump over bumps when unladen.

Rodeo’s 2.6 litre petrol engine remains unchanged, but the 2.8 litre turbocharged diesel (now unique, since its competitors have all gone to naturally aspirated oil-burners) gained some improvements.

The injector nozzle has five smaller holes to produce finer fuel droplets, the combustion chamber shape was changed to produce a stronger `swirl’ effect as the air-fuel mixture enters, and the turbocharger has modifications to its turbine wheel and housing design.

Power and torque outputs are unchanged, but the claimed reduction in noise seems to be real as that distinctive diesel `clatter’ is a bit less obtrusive.

The diesel’s `workhorse’ role is particularly obvious when starting off unladen in first gear, as its final drive ratio is very short -- it usually made sense to start off in second since first gear runs out of legs almost as soon you start moving, but that does give the vehicle prodigious load-carrying ability as maximum torque arrives at just 2300rpm.

And our test vehicle’s 4WD would be ideal for those whose work takes them off the beaten track - we admittedly tried it in deep sand without a load, but the diesel would seem unlikely to give up easily.

An engine-speed of 3,000rpm on WA’s 110kmh open-road limit seemed a tad high for a diesel, yet it felt very comfortable and fuel consumption averaged out at 9.1 L/100km (32mpg).

It was at times almost difficult to be sure which was doing the most work -- power or torque -- since the turbocharger makes the diesel a very willing performer over a wide range of rpm, and at highway speeds it accelerates with a definite forward surge that makes gearchanges unnecessary.

In 1989, its first year on the market, Rodeo attained a barely credible four percent market share, but has since grown in stature to the point where it last year was Holden’s third-biggest seller behind Commodore and Barina, capturing over 22 percent of the light commercial sector.

That market is now more competitive than ever, but with its very tangible improvements this new model could prove even more popular (especially the diesel `tonk-a truck’ version...)

NUTS`N’BOLTS - Holden Rodeo LX Space Cab diesel 4WD