|
Mercedes Benz make Powershift available on Axor
Mercedes-Benz launched the 12-speed Powershift automatic transmission some months ago for Actros customers. Now it is to be made available for certain Axor models, and Export & Freight has had a chance to put the new combination through its paces.
The Powershift transmission will be available initially for the 1843, 1840 and 1836 Axor models. Early 2008 will see its adoption extended to the three-axle model 2543 to 2536 6x2-versions.
Powershift is about three things: economy – through optimised gear changes and a reduction in clutch abuse; productivity – as a result of a considerable weight saving and driver comfort – which, as we will come to in a bit, translates directly into safety.
It is somewhat worrying that it was two decades ago when probably precisely the same comments were made about MB’s EPS transmission when it was launched. EPS was – at best – a partial success. Powershift – along with Volvo’s I-Shift transmission – takes the auto box to a point at which it is no longer a case of arguing in favour of the genre, but of attempting to make a case for the continued use of the manual box. But enough of the hyperbole – at least for the moment; how does the thing work?
Powershift has lost its weight – some 60 kilos when compared to the outgoing Teligent unit – by dint of reducing the number of ratios to 12, and losing the synchromesh, which have been replaced by a so-called layshaft brake. In conjunction with the latest control technology acting in tandem with extremely sensitive actuators, Powershift becomes a constant-mesh box that allows rapid yet smooth automatic shifts.
Whilst Powershift has lost four ratios for going forwards, it has actually gained two for the other direction, and this is considerable cause for joy. Essentially, a Powershift-equipped Merc can now go backwards quicker than before – useful for those got the wrong farm and you’re not turning that thing around in here moments – but also a lot more slowly than previously – meaning that rather more measured progress can be made towards either the loading dock or the dropped trailer can be made. It’s altogether less random, and, as a result, likely to be more than welcome.
 Easy Manoeuvring
In addition to the four reverse cogs, Powershift also boasts a Manoeuvring Mode. Depress the dashboard-mounted switch to engage this, and the engine is limited to a maximum of 1000 rpm, eliminating the prospect of surging backwards. In addition to this feature, the new transmission also boasts a rather useful Rocking Mode. This simply automates what drivers have been doing since the start, and allows the transmission to be shifted between first and reverse in order to extract the vehicle from the mire.
And so to Turkey, and, more exactly, the Taurus mountain range, which lies between Antalya and Aksaray, home of the Mercedes-Benz Turkish truck plant. If you desire to go from one to the other, the mountains lie in the way, and over you go. A succession of long climbs followed by steep descents is the order of the day. But here’s the kicker. Get it wrong in the morning, and there’s a better than good chance that one’s relatives will be dividing your possessions by nightfall. The Taurus Mountains look lovely, but they’ve snagged more than their fair share of both trucks and – sadly – drivers.
It doesn’t end there. On either side of the mountains lie flat roads. Which would be cool, if they were empty flat roads. They’re not: when Turkey drives, it does so with a passion, and in a variety of vehicles. Horse carts share the asphalt with a Cook’s Tour of the auto business, and everyone wants to get on. Think 3-D pinball with the added beauty that is the Turkish long distance bus, and you have a heady mixture. And not a bad proving ground truck.
 Smooth & Fast
As with Teligent, Powershift is an easy ‘box to get to know. Fire the engine up, depress a button on the selector – mounted on a fold down arm on the side of the driver’s seat, dip the throttle and away you go.
The first thing you notice is just how smooth - and how fast – the up-shifts are. Powershift seems to like to start in second at 40 tonnes, and there is only the slightest sensation of anything happening as it moves on up the box. Rather strangely, it seems to like to hold off from getting to top, seeming to prefer eleventh for quite some way into the green band. Very quickly, one learns to feather the ‘box on the right foot, and, if this doesn’t result in the required shift, one still has recourse to a manual over-ride. Here a word of caution. Either we’re getting old and slow, or Powershift has gotten a lot quicker: on a number of occasions, we went for a downshift at the same time as the ‘box did. Two downshifts for the price of one may be a bargain, but it’s not always appropriate. In time, you find it easier to cede the decision making process to the truck, and get on with enjoying the scenery.
It’s been said before, and we’ll make the point again. However well acquainted one is with a truck and its attendant gearbox, there will always be a tendency to let the attention wander during gearshifts. At this point, our friend at the wheel of the Turkish long-haul bus hoves into view, and the result is ruin desolation and despair. The automatic transmission allows one to spend time looking out of the window, and, whilst the buses are still there, they become manageable. So to do the horse carts, venerable BMC and Otosan eight-wheelers and, more pertinently, the Turkish pedestrian, for whom the notion of reclaiming the streets is one that has been taken to heart. However good you are behind the wheel, you can never be safe enough. Powershift allows one to be cautious.
 Easy Does It
A few years ago, sticking a bunch of occasional drivers into trucks and sending them up a mountain in 40 degree heat would have resulted in mayhem and carnage. The air would be thick with the stink of clutch and the scream of head gasket, and they would have been calling in the wreckers from four corners.
Not a bit of it here. We’ve always reckoned that the happiest way to go up hills in hot weather is to be one gear low and light on the foot. 1500 rpm and not too much by way of gas seems to be the way, and Powershift apes this approach. The result is measured progress without too much by way of activity on the temperature gauge. Coming down the other side, and the Voith retarder takes much of the sting out of the descent; Powershift drops down to around seventh, the rev counter explores the top end of the yellow band, and save for a bit of check braking, the Axor’s discs remain fairly cool.
Teligent was getting on a bit, and I-Shift had become the ‘box to beat in the auto stakes. I-Shift now has a major competitor to cope with. Comparing the two in isolation is rather pointless, but that Powershift can be spoken of in the same breath as the Volvo box is high praise indeed. We believe that the era of the automatic transmission and the heavy truck has now very much arrived. Three years ago, it was a case of arguing for an auto box from a default manual position. Powershift changes this for MB customers; try as we might, we can’t fault the thing.
|
|
