Mercedes-Benz GL-Class 2006 Review

What we liked
>> Smooth, super-capable drivetrains
>> Serious offroad ability
>> Comparatively generous third row

Overall rating: 4.0/5.0
Engine, drivetrain and chassis: 4.5/5.0
Pricing, packaging and practicality: 4.0/5.0
Safety: 4.5/5.0
Behind the wheel: 4.0/5.0
X-factor: 4.5/5.0

OVERVIEW
The introduction of the GL-Class to Australia is more about 'Benz than us; more about product mix than market. It's the first full-size (seven-seater) passenger SUV from Mercedes-Benz, American-built and largely directed at the huge US SUV market. Lord of the Benz line-up, the company will be happy if it moves just 400 GLs here a year.

Like the boxy, brawny and iconic G-Class, the GL is a serious offroader. However, in its new iteration it has moved up a class in terms of luxury, fit and finish. No news you say -- Benz can do all that very well… Thus it’s 'G' that's the operative. For the GL to eclipse the consummate 'G Wagen' -- not sold Down Under for many years but seen occasionally as private imports -- the luxury version must wear sturdy boots.

The GL uses MB's 4MATIC permanent four-wheel-drive system, gets the company's top offroad package and can tow 3500kg. It has a unitised steel body rather than the G-Class' ladder frame-type design but this takes passive occupant protection systems into the prestige car realm and the use of lightweight steel promises comparable offroad strength.

Based on the mid-size M-Class but with the dimensions of the R-Class touring wagon, you won't help but notice Benz's 'Gentle Giant' GL-Class tread over town and country.

PRICE AND EQUIPMENT
Before the likely appearance of a range-topping AMG model, the GL Class line-up for Australia starts with the 3.0-litre turbodiesel V6 GL 320CDI priced from $103,900 and packing 165kW/510Nm. Next up, the 5.4-litre petrol V8-engined GL 500 is priced at $146,900 and good for 285kW. Both engines meet Euro IV emissions standards and are teamed with the 7G-TRONIC automatic transmissions as standard.

The 'Off Road Pro' engineering package, also standard fit on both models, has 'shift-on-the-move' low-range and includes MB's AIRMATIC level control system with active suspension damping, '4ETS' traction control, brake assist, ESP with trailer stabilisation program, hill start assist and downhill speed regulation, and ABS with off-road mode.

Distinctions between the extensive standard equipment lists for either model include dual-zone climate control, 'Artico' (leather-like) interior trim and 18-inch alloy wheels for the GL 320 CDI, while GL 500 gets multi-zone climate control, leather interior, 19-inch wheels, heated second-row seats, DVD navigation system, glass electric sunroof and remote-control electro-hydraulic tailgate.

Both models have a fixed sunroof over the rear row, cargo cover, park assist, electrically-adjustable front seats, 12-volt sockets, tinted power windows and tyre pressure loss warning… And alas, a space saver spare wheel.

Options include DISTRONIC radar-based proximity control and cruise control system, 20-inch wheels, reversing camera, Harmon Kardon audio system and DVD entertainment system with seven-inch LCD monitors in the front head-rests. Both models have a steel rear underbody guard but a chrome package is available comprising stainless-steel underguard for front and rear, chrome-look roof rails and cross bar.

The third-row seat, which is folded electrically and stows flat, is also an option for $3900. The five-seater gets additional underfloor stowage in lieu of the third row.

The GL might be built for big American families but interestingly DaimlerChrysler Australia says more than half of the early orders have been for the seven-seat version.

MECHANICAL
The 'entry-level' GL 320 CDI is equipped with Mercedes' accomplished 3.0-litre turbodiesel V6 which can manage 0-100km/h in 9.5sec and has good torque spread for real world in-gear performance. Consumption for the diesel model is a claimed 9.7lt/100km.

Like its diesel stablemate, the 500's all-new aluminium V8 has already seen service in a number of Mercedes-Benz models. Debuting in the S 500 earlier this year, it's a modern design that features variable valve timing on both intake and exhaust camshaft adjustment and an elaborate induction system that Benz claims substantially improves efficiency.

Both engines are mated to the 7G-TRONIC seven-speed automatic transmission which has manual function accessed via gearshift buttons on the back of the steering wheel.

The really interesting kit is all the offroad assistance. The GL's 4MATIC system employs a two-speed transfer case with a low-range ratio and full differential locks for the transfer case and rear axle. The transfer case uses reduction gearing (2.93: 1) while multiple-plate viscous clutches provide up to 100 per cent locking at the rear axle and centre diff. The front axle is also equipped with an 'electronic' differential lock which allows steering control, otherwise hampered by a mechanical lock.

Traction is maintained by MB's 4ETS which sends drive torque to the most planted wheels, even if it happens to be only one.

The GL's ABS is specially designed for offroad conditions -- namely loose, rough surfaces and steep descents -- enabling wheels to lock in certain situations. Upon a steep descent, the driver can set the DSR to remain under a selected speed, while hill start assist will prevent the big GL from rolling on uneven ground when moving from rest.

The GL gets a modified version of MB's AIRMATIC level control system which raises ride height up to 110mm for a maximum ground clearance offroad on 307mm. The level will drop to 182mm for high-speed situations (over 140km/h) automatically, from its basic or highway height setting of 197mm. It was the shorter GL, Officer…

The ADS (active damping system), fitted standard, employs adjustable gas shock absorbers to provide four ride characteristics: soft compression and rebound, soft rebound and hard compression, soft compression and hard rebound, or hard compression and rebound.

At higher speeds the system will reset to the 'skyhook' modes (soft rebound and hard compression or soft compression and hard rebound) to allow for body roll. GL also has front and rear torsion bar stabilisers and gets double-wishbone front suspension and a four-link rear axle.

GL's brakes need to be, and are, large and durable. The four wheel discs are ventilated and as noted above, assisted with offroad capable ABS and allied systems.

PACKAGING
Sharing the R-Class' size and 'dynamic space' concept, the GL is comfortable up front, spacious midships and offers clever cargo and rear seating options. Generous interior dimensions allow good headroom through to the third row, although the roof-line undulates with the climate-control vents and this may affect load space versatility.

Fold-flat seating, electric for the third row, allows up to 2300lt of load space. Whilst the optional rear row is tight for knee room, it provides wide armrests and individual seats. Opening rear windows (though you must ask the driver) and the fixed sunroof (with sunblind) serve to reduce the confinement at the back of the bus.

Access to the third row is via the split-fold second row which is easy enough, but rearmost occupants must pull a strip to release the seat for exit. If the front seat obstructs the second row from folding it automatically slides forward, and will resume its place once rear passengers are seated.

The Artico 'man-made leather' is, and feels like, manufactured leather and is rather characterless but likely not to age like the genuine article.

Grab handles alongside the centre console and doors are useful and an authentic offroad inclusion, so too the long-haul 100lt fuel tank (997km claimed range in the case of the diesel).

SAFETY
Mercedes says its PRE-SAFE system offers benchmark safety levels for the SUV class. The program works with the sensors in the handling control systems (ABS, ESP and BAS), detecting situations beyond driver control and preparing passive safety components such as seat-belt tensioners for possible collision. Open windows and sunroof will be closed and the front passenger seat is moved to the best position for the airbags and seat-belt system to offer maximum protection.

GL has airbags all 'round, including windowbags through to the third row of seats or D pillar, and a clever control unit with crash sensors that can determine the severity of an accident to deploy the front adaptive (two-stage) airbags, and the side and windowbags as required. The airbag control unit works with a central 'crash command' system that will activate the seatbelt-force limiters and NECK-PRO active head restraints, which provide support to the head in the event of rear impact. The command centre also utilizes a roll-over sensor.

Mercedes says the use of a unitised steel body "forms the ideal base" for passive occupant protection, allowing for a three-piece floor assembly with strengthened centre section to create a sturdy "backbone" for rigidity. Reinforcements include side members up front, central and rear seat cross-members, triple-shell A, B, C and D-pillars and partially double-walled high-strength roof frame.

The GL's ESP includes a trailer stabilisation system which identifies critical driving situations while towing and applies individual wheel brakes as required.

COMPETITORS
The luxury SUV market might've peaked but it's sure packed. Starting with the 'cheapies': Volvo XC90 offers seven seats with third-row air-con, leather and V8, if you want, for $85K but can't hope to follow in the GL's off-road tracks. Same goes for Subaru Tribeca.

If you can do without the third-row seating there's the bigger engined VW Touaregs, which by the time you option up to somewhere near the GL's equipment list is comparable price-wise, at least. Jeep models like the Commander might also garner some cross-shopping.

Given the badge and scope of the GL, the real competitors are the latest from Audi, BMW and, of course, Land Rover.

Audi's Q7 offers full-size, capable off-roading and impressive standard fit and tops out at $116,800 -- at least until the V12 version arrives. The upcoming BMW X5 will be offered with a third-row but in its current form is a strict five-seater. The V8 X5 costs around $10K more than GL.

Range Rover has both its Vogue and Sport models which are both five seaters but offer comparable luxury and off-road ability.

To check out CarPoint's car comparator preloaded with the GL's opponents click

ON THE ROAD
Eager for Queensland's exclusively-4WD Fraser Island, the GL gobbled the largely highway stint between Brisbane airport and Rainbow Beach with the composure you'd expect from a Mercedes. Both the diesel and V8 petrol variants get up to speed quickly and will overtake traffic with ease despite their bulk -- helped by prompt downshift response from the need-no-introduction, or intervention, 7G.

No prizes for guessing the 500 did the on-road section best of all. The V8 is an impressively calm but muscular powerplant with just a hint of burble for the enthusiasts.

You pay at the pump, but perhaps not as much as you'd expect -- the example we checked on the return journey the next day (including some off-road) logged an average of 15.1lt/100km. Impressive, even if it is more than the company's claimed 13.9lt/100km figure.

Mercedes says around half the inital GL customers will opt for the 320 CDI. You can expect this to be more frugal and closer to matching Mercedes' claim of 9.7lt/100km. A verdict on how close will have to wait until we park ourselves in a road-test GL CDI closer to home.

MB claims a drag co-efficient of 0.37 for the 2440kg-plus GL -- actually reasonably slippery for a barn-door offroader... It also says it has made great efforts to reduce wind noise and has been successful although road noise from the wide all-terrain tyres was noticeable.

Disappointingly, so too was the racket from the suspension on the offroad sections of the test loop.

The GL conquered Fraser's rutted sand tracks easily and despite their pronounced crowns didn't 'scrape' the underside at any stage -- ground clearance is prodigious when the adaptive level system is set to its highest (307mm) of three settings.

Approach and departure angles are also impressive with the offroad experts along for the drive vouching for the big GL's overall competance. Cycling the active damping system through its four stages made discernible differences to ride comfort on the test route.

Though we'll leave the serious offroading verdict to the experts, this bush rookie can attest to the ease of piloting the GL in all the conditions encountered. The big Benz's (speed-sensitive) steering is light in the rough stuff but still manageable even in the more gnarly terrain that can divert the vehicle in unwanted directions.

The downhill speed regulation was especially useful on steep declines where vision to the trough was obscured. Creeping towards the driver-selected speed limit will bring up an unobtrusive warning signal on the instrument dash.

Passing open troopies loaded with Fraser day-trippers in the leather-lined, climate-controlled GL was almost embarrassing but the GL's off-road credentials kept us looking serious, not to mention trim and nimble by comparison. A gentle giant indeed...