Truck transmission trends
Truck buyers in Australia are spoilt for choice with the range of transmission options available today. Prime Mover took a look at past, current and emerging transmission trends.
There was a time when the ability to shift gears in a truck transmission was considered almost to be a black art akin to water divining. Back when a 250hp vehicle was the king of the road, trucks relied upon rudimentary manual gearboxes to get the load rolling and to negotiate up and down hills.
During the last century, some manufacturers went as far as fitting a second auxiliary or “joey box” that multiplied the available ratios and made twin stick shifting an even more specialised skill for drivers, especially those capable of compound shifting by moving up a gear on one box, concurrently moving down a gear in the other.
The availability of higher horsepower engines, with maximum torque being available over a wider range of engine revolutions, changed the requirements for truck transmissions from being merely a means to reach a destination to being a critical factor in getting there more efficiently.
While constant mesh gearboxes still remain popular with many operators today - their robust design contributes significantly to their reliability - one of the challenges still associated with them is the shortage of drivers with the skills to use them correctly.
Despite that dwindling pool of skilled drivers, some people still say you’re not considered a proper truck driver if you let the truck do the shifting – even though the constant double clutching and rowing through a multitude of gears can be a source of repetitive strain injuries to the left side limbs of those very drivers.
That's why constant mesh gearboxes started giving way to synchronised mesh manual transmissions in Western Europe during the early 1990s.
Manufacturers like Volvo, Daimler-Benz, Iveco and Scania lead the way to providing gearboxes that were more forgiving on the driver and even gentler on the rest of the drive train. Currently, the Chinese vehicle-manufacturing juggernaut seems to be adopting similar synchromesh technology for its own medium-duty and heavy-duty trucks.