LAND ROVER has revamped the oldest vehicle available new in Australia – the Defender – though you may not notice immediately.

The biggest changes to the latest, L316 Defender model (that dates back to 1948 and was last significantly revamped in 1984) are not immediately obvious since the same ‘110’ wagon and ‘130’ four-door utility (referring to the wheelbase length in inches) architecture choices have been retained.

From the driver’s seat, you are most likely to notice the ‘reprofiled’ bonnet that features a hump as a result of a taller engine installation.

It is the only real visual clue to the new vehicle – along with the spelling of ‘LAND ROVER’ instead of ‘DEFENDER’ on the bonnet’s trailing edge.

But the real changes lie beneath the same old skin including a new turbo-diesel engine and manual transmission, quieter interior, redesigned dashboard and a forward-facing third-row seating availability for the first time (in the 110).

A 2.4-litre 16-valve common-rail four-cylinder turbo-diesel engine derived from a unit found in Ford’s VM Transit van range is now the Defender’s sole powerplant. The new engine provides a 20 per cent boost in torque.

Described as a major step forward in refinement and driveability, it delivers 90kW of power at 2200rpm (with 90 per cent available from less than 2000-4350rpm) and 360Nm of torque at 2000rpm (315Nm present from 1500-2700rpm).

It usurps the old 2.5-litre five-cylinder turbo-diesel unit that produced 90kW at 4200rpm and 300Nm at 1950rpm and dated back from the 1990s.

The new cast-iron block engine is Euro IV compatible in markets where high-quality diesel is available, but can also cope with high-sulphur and variable quality fuels too.

It features an alloy head, Denso common-rail fuel injection with solenoid driven fuel injectors that help reduce diesel combustion noise dramatically, and a Garrett variable-geometry turbocharger.

Land Rover says that its lubrication and sealing systems are also specially developed to cope with the wide range of operating angles that the Defender is expected to experience in the bush.

Other modifications for this application include relocating the alternator above the engine for improved river-wading capabilities. This also explains the bonnet bump.

As before, torque is evenly transmitted full-time via all four wheels, with high- and low-range gearing included. Along with ABS, the 110 offers traction control for greater off-road ability while the 130 does not.

A new single-mass flywheel has been installed, with the clutch being easier and lighter to use than before.

The engine also benefits from improved anti-stall characteristics as a result of the injection software monitoring and precisely altering fuel delivery.

The only gearbox on offer is a six-speed manual transmission that is new to the Defender. Based on the unit found in the Discovery, it steps in for the old five-speeder. As before, no automatic is available.

Dubbed GFT MT 82, the new manual eclipses the old gearbox by utilising a wider spread of ratios for improved off-road and cruising ability.

The combined fuel consumption average for the 2041kg 110 is 11.0L/100km (11.1L/100km for the 2120kg 130).

Urban and extra-urban results meanwhile, are 13.5L and 9.5L for the 110 and 13.6L and 9.7L for the 130 respectively.

For the record, the Defender’s 132km/h top speed and 15.8 second 0-100km/h ‘sprint’ time makes it one of the slowest new-passenger vehicles money can buy.

The Defender’s box-section ladder-chassis construction remains as before, as does the live beam axle and coil springs front and rear suspension system, albeit with new anti-roll bars. Axle articulation on the 110 wagon is now 655mm.

Inside, the makeover brings a dose of Discovery to the Defender.

While there is no more space than before, the ergonomics get a big shot in the arm thanks to an all-new facia that Land Rover says is “… better integrated, more robust and functionally superior to the old unit, whilst still entirely in keeping with Defender’s character.” Supporting these claims literally is the installation of a single moulding for the dashboard that is now mounted on a steel rail to eliminate squeaks and rattles. It is also still ‘short-depth’ as so not to encroach on the already tight cabin dimensions.

No longer offset to one side, the instrumentation is straight out of the latest Discovery, and introduces all-LED illumination. A 14-litre storage bin and extra shelving, along with the option of better audio systems are also part of the new cabin packaging.

However, airbags of any description are still not available.

On the ergonomic front, the left-front occupant now has a heavy-duty horizontal grab handle for sturdy two-hand support, while a complete rethink of the heating and ventilation set-up includes a broader range of temperature settings, improved heating and cooling performance – now with standard air-conditioning – and the implementation of side-window demisters.

As a result, the Defender’s iconic vent flaps underneath the windscreen no longer function.

The stadium-style seating arrangement has also improved from taller and more supportive front seats, while Land Rover claims the new asymmetrically-split, three-person, second-row bench brings easier folding-down.

For $2000 more on the 110 wagon, buyers can opt for a pair of forward-facing third-row chairs (instead of side-saddle seating) that can be accessed via the second row or through the back door, and can be folded and stowed sideways in the load space.

Land Rover provides three-point lap-sash seatbelts for all occupants, uses vinyl and cloth trim coverings, and has upgraded sound insulation that – combined with the quieter engine and higher gearing – help slash mechanical and road noise levels.

This is probably going to be the biggest hit for buyers who have had any contact with previous models.

The Defender’s chief program engineer, Gary Taylor admits that for many people, “… the step change in Defender's refinement will be one of the most welcome advances not only are noise levels significantly lower, but sound quality is transformed too.”

There are no plans to bring the short-wheelbase ‘90’ model – for now.

The outgoing Defender was introduced in 2002, and averaged global sales of 25,000 annually in 130 countries. It serves 60 military services around the world, as well as a host of charity, governmental, rescue, aid agency and agricultural organisations – to name a few.

Debuting at the Amsterdam Motor Show on April 30, 1948, nearly 1.9 million have been sold. A Series II followed in 1958, followed by the Series III in 1971, while the current vehicle is based on the 1984 revamp.