Volvo's I-Shift 12-speed automated transmission has been around for several years, but until a few months ago it was only available with the Swedish manufacturer's 9 and 12- litre engines. In May up-rated versions of the box hit the streets, with three new models.

The V2812AT and VO3112AT - capable of handling torque outputs of 2800 and 3100Nm (2065 and 2286ft-lb) respectively and a new V2512AT for use with the D13 upto 130 tonnes GCW.

These long awaited transmissions enabled Volvo to offer its FH16 customers a much-needed alternative to the knife-edge existence they had endured with the Volvo powerhouse flagship and its manual box. In last year's April issue of ROADWAY we drove the Euro 3 610hp FH16 at 40 tonnes and commented on the potentially precarious procedure of an up-shift under full load. With the engine revs creeping over 1400rpm you could feel the immense torque unwind momentarily from the driveline as the clutch was depressed.

We have not heard of too many snapped half shafts or destroyed clutches in the FH16, but their drivers tend to own them or are sufficiently respectful and too experienced to risk the consequences of abuse. But with the arrival of an electronically controlled automated gear-changing assistant, FH16 drivers can sit back, relax and enjoy the ride. And their employers can sleep easier in their beds.

But Volvo's second-generation I-Shift transmission is about more than just the FH16. Improvements have been made across the range of transmissions. Volvo claims that the new I-Shift is lighter, quieter and is more compact than its predecessor. Lower internal frictional forces are credited with helping to improve fuel economy and the transmissions are available in fine tune for long haul, distribution and construction use down to 26- tonnes GVW. The entry level for I-Shift is in Volvo's FM 6x2 rigid. Powered by the 9.4-litre D9B Euro 4 engine outputs start at 300hp and 1500Nm (1106ft-lb) of torque and rise to 380hp and 1700Nm (1254ft-lb).

The V2412AT I-Shift transmission comes with a range of software options that start with a basic mode and rise through comfort, distribution and construction, fuel economy and comfort (EcoRoll) and long-haul and fuel economy to an optional enhanced system with manual shift available in the auto mode and a kick down facility on the accelerator pedal. Similar options exist for the FH range with its D13A lead power train from 400 to 520hp, and fuel economy versions of the new I-Shift transmission can be specified with Volvo's EcoRoll system, which disengages the drive when neither power nor engine braking is needed. The new V25 and V31 transmissions are specialised for heavy haulage operation. A heavy GCM control features in the V3112AT that optimises gear selection for high gross combination weights up to 180 tonnes.

FM340

We took a recent opportunity to drive two new Euro 4 models fitted with the latest I-Shift transmission. Volvo's FM340 6x2 rear steer is proving to be a popular long-haul distribution vehicle. Its sub 8-tonne chassis weight means it can carry a 16-tonne payload and still be highly manoeuvrable in all but the tightest of situations. Its 9.4-litre engine was exceptionally well matched to the transmission and single reduction rear axle. Developing 340hp at 1900rpm and its maximum torque output of 1600Nm (1180ft-lb) between 1200 and 1400rpm, the engine needs to be kept spinning in this relatively narrow rev band for optimum economy and performance.

From standstill, the transmission shifts up the box incredibly fast thanks to the absence of synchros in its base unit. Synchromesh is provided electronically via the engine and transmission control units. Once cruise is engaged the long-haul and fuel economy software made shifts up and down the box to maintain road speed and keep the needle in the green band as we travelled along a mix of undulating country roads, dual carriageways and motorways. Early automated transmissions had a habit of shifting down too soon and skipping between gears, but the new I-Shift holds onto gears well, taking maximum advantage of the torque.

When driving around town there is sufficient sensitivity in the accelerator to control gear-shifts and once drivers are educated that the right pedal doubles as a gear lever, the option to switch to manual should only be taken in the most demanding of situations or when driving off road on difficult terrain. Once we were outside the city limits we found the truck is best left to its own devices. By resuming the cruise control the shifting software will drive the truck up to the desired speed, quickly and efficiently.

One major criticism levelled by drivers against automated transmissions is their inability to offer inch-perfect control while manoeuvring or reversing up inclines. Some manufacturers have included a crawler mode on their transmissions to address this problem, but Volvo claims that the automated clutch control with I-Shift is so precise it does not need to resort to this. We put the new I-Shift's creeping ability to the test in the FM340 6x2. Having made a three-point turn in a tight yard we reversed the fully loaded FM into a loading bay. At all times during the manoeuvre the transmission responded to our throttle inputs smoothly and gradually until we had the truck inching backwards. We did not detect any snatching and the truck did not lurch even when a bit more gas was required to overcome the gravitational effects of the slight incline up to the bay. We were impressed and feel that the level of control built into the new I-Shift is an improvement on the fairly high standard Volvo had achieved with its older version.

FH16 580

The new FH16 has one of the most powerful drivelines in its class. The 660hp version is only a sensible option for UK operators involved in heavy haulage. This said its 610hp predecessor has proved popular as a prestige tractor among general hauliers and a handful of 660s will no doubt be operating at 40 and 44 tonnes in the UK for the same reason why people buy the Ferrari Enzo; because they can. The more practical version is the FH16 580. With 2800Nm of torque being generated between 1000 and 1450rpm it will lift 40 tonnes over the steepest alpine pass with ease and keep it under control during the descent thanks to 425kW (570hp) of retardation from the standard Volvo engine brake and this can be increased to 865kW (1160hp) with a hydraulic retarder.

But as we have already said, the biggest story is the addition of I-Shift. Development of the transmission has resulted in a much stronger, fastacting gearshift system that does not interrupt torque delivery for long enough to allow damage to the transmission or drive train.

The V2812AT in the FH16 580 driven here has a direct drive top ratio and is only suitable for 44-tonne operation. A V3112AT transmission - with overdriven top gear - is the only transmission option for the FH16 660 and also must be specified for GCWs over 44 tonnes in the 580. The driving experience is closely akin to the FM and despite the FH's 44-tonne GVW doing its best to slow down proceedings 2800Nm of torque and lightening quick shifts, courtesy of the automated transmission, made nonsense of the load.

Compared with its Swedish rival's 16-litre V8 flagship R620 and its Opticruise three pedal auto box - driven last year - the FH16 580 is in another dimension. Shift speeds are considerably quicker and much smoother, and even at low speeds turning out of side roads I-Shift changes up fast enough so momentum is not lost through trailer drag.

We drove through one narrow town making a very tight left turn into oncoming traffic waiting at a set of lights. With no room for manoeuvre the turn required inching forward as mirrors and clearances were constantly checked. With a manual transmission we would have been slipping the clutch in first or second gear to ensure the required degree of control, and worrying about what this was doing to the driveline, but I-Shift handled the manoeuvre perfectly and we squeezed round the turn with millimetres to spare under complete control.

We would not have wanted to try this in some other two pedal autos. Out on the open road the FH16 is a pleasure to drive now the worry and effort of gear shifting is gone. Accelerating away from roundabouts on the cruise control allowed the truck to flex its muscles with no fear of driveline damage or loss of traction and its apparently effortless progress left even the 7.5-tonners for dead.

Conclusion

There is no doubt in our minds that Volvo's new I-Shift leads the way in the heavy truck transmission stakes.

The manufacturer says it has removed the kick down facility from the standard transmission and only offers one version where manual intervention is permitted in fully automatic mode, following requests from customers. This is allegedly to prevent drivers using too much fuel.

During our brief test of two versions of Volvo's new I-Shift we can safely say that its decision can be fully justified by the transmission's performance. The old adage that an automated transmission will not be as good as a really good driver in a manual may have to be rethought in the case of Volvo's latest offering.