UPDATE, January 5, 7pm: The story story 2018 Mercedes-Benz G-Class exterior leaked was originally published this morning, with only leaked photos and details reported in the overseas press. Although Mercedes-Benz has yet to hand down official undisguised photos, the company has now at least revealed key technology details. This story has been updated to reflect that release.
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Photos of the new Mercedes-Benz G-Class have been leaked ahead of its debut later this month, while Mercedes-Benz itself has handed down a press release that talks up the new G-Wagen's off-roading ability.

Thanks to spy photo set after spy photo set, we already already know the new G-Class won't look too different to the current, long-lived model.

Now, with these leaked undisguised photos published by Autoweek.nl and Autobahn, we can finally see how much, or how little, the styling has evolved.

Despite looking like a dead ringer for current G-Class, the new version has an all-new body with more rounded edges, a slightly less slab-sided appearance, and a shallower glasshouse.

Leaked images aside, Mercedes-Benz has today confirmed the capabilities of its new G-Class have been tested and rated against the 1445-metre-high Schöckl mountain.

Located near the new model's production home in Graz, Austria, the course includes gradients of up to 60 per cent and lateral inclinations of up to 40 per cent.

In all, the 5.6-kilometre route was tackled through 2000 kilometres of driving for each vehicle that was used in the development program, and Mercedes says it did so with "noticeably more control and comfort" than the ancient outgoing model.

A ladder-frame chassis underpins the new G, matched to three 100-per-cent differential locks and a low-range ratio. Independent suspension is featured with a double wishbone design at the front - fixed directly to the frame rather than through a subframe - and a rigid axle at the rear, all developed collaboratively between Mercedes-Benz and offshoot Mercedes-AMG.

Suspension spring/rebound travel is listed at 85/100mm at the front, and 82/142mm at the rear.

"Specifically for the G-Class, the new front axle is designed in such a robust way that the off-road performance and off-road capabilities of its predecessor are maintained and partly even surpassed," the company says of its new G-Wagen.

The big retro-styled SUV has a 31-degree approach angle, a breakover angle of 26 degrees, and can ford water that's up to 700mm deep - an improvement of 10mm on the old model. Ground clearance is up 6mm to 241mm.

Drive is sent to the ground through a nine-speed automatic transmission, with the four-wheel drive system normally configured to deliver 40 per cent of the torque to the front wheels, and 60 per cent to the rear.

A new G-Mode driving mode is featured, engaging the moment any of the three differential locks is engaged or when low range is selected. Mercedes says this setting will adapt the adjustable damping, steering, throttle and transmission - just as you'd expect on sports cars, but for an off-roading bent.

Although the car has not grown in width, the cabin is said to be significantly wider, and there's also a claimed 15cm of extra rear seat leg room.

Mercedes-Benz revealed the G-Class' interior last month, so we already know that while the outside is very much a gentle evolution of the current car, the inside has been given a thoroughly 21st century redesign.

In top-spec models, the dashboard features two large 12.3-inch screens designed, at least when the car's switched off, to look like one giant display. Elsewhere, switches, controls and interfaces are all shared with other models in the Mercedes-Benz range.

Nods to the G-Class' off-roading heritage include a dashboard design that's blockier than the ones used in other Mercedes-Benz models, and the grab handle ahead of the front passenger.

As you'd expect from a modern luxury conveyance, the new G-Class is available with acres of quilted leather, soft-touch materials, metallic trim, and realistic looking slabs of wood.

Australia

Mercedes-Benz Australia has told CarAdvice the new G-Class will arrive down under around the middle of 2018, with the AMG G63 to be the sole model available at launch.

A more frugal and off-road-friendly G350 diesel variant is pencilled in for later in the year.