At first it all sounds a tad unrefined and cumbersome: constant mesh transmission, Mercedes PowerShift Offroad, Offroad package. Power that resonates from the choice of words. Stylish exterior, tough core? The new construction Actros, a 2646 K 6x4 with air-suspension tandem, stands as a kind of universal tipper before the tester, seemingly suspecting his misgivings. Clad in the stylish looks of the new road-based Actros, even the solid guard plate for the oil sump cuts a fine figure: a perfect marriage of form and function.

Even standing still, the exterior of the construction-site Actros manages to dispel a few misgivings about its cumbersome, rugged credentials. Once up in the medium-length cab, your on-road specialist feels instantly at home in the off-road Actros. Stylish instruments as on the road-based best-selling model, the familiar seat and mirror adjustment options. All the switches are where they should be. Even the gearshift seems identical: Mercedes PowerShift Offroad delivers the sort of experience the asphalt cowboys will be familiar with - driving what should essentially be an unrefined construction-site vehicle comes across as extremely comfortable.

Get in, belt up, and away you go. Just do not forget your tachograph card. Or the daily checks - but your friendly test-drive companion from Mercedes-Benz has already seen to that. The transmission computer has already selected third gear as the right choice to move off. Given the low vehicle weight of just under 26 tonnes for the 456 hp and 2200 Nm and a short final drive ratio tailored to off-road operations, this philosophy definitely reduces wear and tear on the clutch. At idling speed the connection is already made. Slipping clutch? Not here.

The assembled PowerShift electronics demonstrate their Mercedes-Benz roots as the truck accelerates. True to the well established theory of large gearchange steps, the 2646 shifts, wherever possible, from third to sixth and then straight into ninth. The transmission computer simply loathes wasting time and fuel. After ninth gear, the eleventh, and then the twelfth shaft is engaged, getting you up to cruising speed in no time at all.

At 80 km/h on a dual carriageway the 11.9-litre six-cylinder engine mumbles away to itself fairly economically in the lower partial load region. Thanks to new planetary axles with long ratios plus overdrive configuration of the PowerShift box, a good on-road/off-road compromise seems to have been reached. Nonetheless, the reinforced transmission dubbed the G 330 comes with a ratio range of 14.9 between first and twelfth gear.

This is even sufficient in more challenging terrain such as Daimler's off-road handling course in Ötigheim. Once there, the adrenalin level of the hitherto utterly relaxed Actros tester shoots up. Churned-up dirt tracks with huge, seemingly bottomless puddles all around, with a few more or less "unnegotiable" mounds in the middle for good measure. Unnegotiable in any case with a "simple" 6x4 tipper, let alone with an automatic transmission, the tester thinks out loud.

"Let Mercedes PowerShift Offroad do the work", as the Mercedes-Benz man prevents the unnerved driver from hitting the switch for manual shift mode. And he should know; after all, he helped develop and test Mercedes-Benz Trucks off-road trucks and the automated transmission. Just select the inter-axle lock - on the Actros it is all perfectly logical with a rotary switch, which prevents the driver from inadvertently activating and deactivating the differential locks in the wrong sequence.

The tipper rapidly picks up speed and now upshifts, perfectly in tune with the rolling resistance, using small gear changes, through the first puddle. The speed stays high, sticking with fifth gear. In the next puddle, the construction Actros dives into a very deep mud pool, the truck suddenly loses momentum. No reason to panic for Mercedes PowerShift Offroad: the automated transmission directly shifts from fifth back down into first gear so reliably it seems it could do it in its sleep. The power at the drive wheels already matches the current rolling resistance. The Actros ploughs through the deep muddy water without getting bogged down.

Okay, the quickly engaged inter-wheel lock does its bit to ensure uninterrupted traction. Switching off the wheel speed synchronisation function was incredibly simple, even for the off-road novice. Ultimately, the unavoidable transmission gearshift sequences went off superbly without any actions on a gear knob or well metered operation of a clutch pedal, leaving the driver with all the time in the world to simply move the differential lock switch up another notch.

Can driving off-road really be that easy? Well not entirely. Before tackling the sizeable steep gradients, the Mercedes man adds a note of caution: "The know­ledge and skill of the driver is indispensable on difficult terrain". He means the tester should now do exactly what he is told, adding that not even the best automated transmission can see - even if the highly sensitive sensors on the new PowerShift Offroad with its tilt sensor that has been further enhanced for off-road operations almost seem to intuitively sense changes in the rolling resistance.

So the tester can now finally do what he wanted to do all along when going off-road: switch to manual mode. In the set first gear the three-axle truck climbs the incline with its locked drive tandem. Almost as if it wanted to show the off-road greenhorn: all-wheel drive? Don't need it. Down-hill - and don't you know it: vertically down - then it is back to the classic response in first gear with no possibility of upshifting and with the breathtakingly muscular auxiliary brake duo comprising the constantly-open throttle valve and engine brake.

Having learned the lesson, the tester again has the "top" speed range in his sights. All the locks off, transmission mode back to automatic, and it is down to business. Plough through puddles, generate bow waves, all to the delight of the photographer.

Although the fun in the water has little to do with proper off-roading, you have the opportunity to try out a useful Mercedes PowerShift Offroad feature there and then. Rapid reversing in the top of the four integral gear ratios. All of which saves time in everyday construction-site operations. During the test drive, however, the photographer, if nobody else, is less than enthusiastic - the bow wave is now a stern wave, lapping in the wrong direction.

At some point though the off-roading comes to an end. The tester is suitably impressed. The Actros is totally unfazed. Only a touch dirty. With safety firmly in mind, the worst is removed manually before setting off home on public roads. It is particularly easy with the tail lights protected against damage from stone chippings: fold the grille out of the way, wipe over, fold the grille back. A small feature that is testimony to the meticulous attention to detail. The new construction Actros is anything but rough, cumbersome and unrefined.

To assist the construction Actros driver even in the most varied everyday situations, Mercedes PowerShift Offroad comes with a range of intelligent functions.

The new functions are operated via a separate console. Activation or deactivation of one or more of these driving or operating aids is indicated in the multifunction display.