Tractorheads with automated gearbox
The automated manual transmission (AMT) is now the standard in the European tractorhead market, representing over 90% of new registrations. Unlike a conventional automatic gearbox (with torque converter, as in a car), an AMT is a robotised manual gearbox: it uses a conventional dry clutch and mechanical gears, but gear changes are executed by an electrohydraulic system controlled by an electronic control unit, eliminating the clutch pedal.
Automated vs automatic vs manual
It is important to distinguish between the three types of transmission available in tractorheads:
- Manual: Mechanical gearbox with clutch pedal and gear lever. The driver selects each gear. Typically 12 or 16 speeds (ZF Ecosplit, Eaton Fuller). Still preferred by some veteran drivers and in markets such as Eastern Europe.
- Automated (AMT): Robotised manual without clutch pedal. The electronic system selects the optimal gear based on speed, load, gradient and route profile. The dominant type in Western Europe since 2015. Examples: I-Shift, Opticruise, TraXon, PowerShift, Optidriver.
- Automatic (torque converter): With hydrodynamic torque converter. Very rare in European heavy trucks, more common in city buses and North American trucks. The Allison 4000 series is the only significant option in Europe, used mainly in fire engines and special applications.
Leading automated transmissions
Each manufacturer has developed its own automated transmission or uses the ZF TraXon:
- Volvo I-Shift: Introduced in 2001, it was the first AMT on the market and remains the benchmark. 12 speeds with Economy, Performance, Off-road and slow manoeuvring modes. The I-Shift Dual Clutch version (2014) was the first dual-clutch transmission for trucks, eliminating torque interruption during shifts. Available with Crawler Gears (2 ultra-slow speeds for precision manoeuvring).
- Scania Opticruise: 12 speeds with GRS (Gearbox Range Splitter) for 24 effective ratios. Famous for its shift speed and smoothness. Scania was the first manufacturer to offer factory Crawler Gears for manoeuvring at speeds below 1 km/h. Shift software is updated with each service revision to optimise performance.
- ZF TraXon: Independent transmission used by DAF, MAN and Iveco. 12 or 16 speeds. The PreVision GPS version anticipates shifts based on topography. The ZF TraXon Hybrid adds an integrated 120 kW electric motor for plug-in hybrid functionality.
- Mercedes PowerShift 3: Developed in-house by Daimler. 12 speeds with Predictive Powertrain Control (PPC) using GPS and 3D terrain data to optimise gears and speed over a 3 km horizon. Compatible with the Actros Active Drive Assist semi-autonomous driving.
- Renault Optidriver: Based on Volvo technology (AT2612). 12 speeds with Optivision (GPS prediction) and Eco-roll (automatic neutral on gentle descents to reduce consumption). The Optifuel system provides real-time driver coaching.
- Iveco HI-TRONIX: Iveco's own development. 12 speeds with consumption-optimised shift algorithms. Includes eco-roll mode and rocking mode to free the vehicle on soft ground by automatically alternating forward and reverse.
Advantages of automated transmission
The reasons why AMT has displaced manual gearboxes in Europe are multiple:
- Fuel savings: Between 3% and 5% average reduction compared to manual driving. GPS-predictive systems (PPC, Optivision, PreVision) add an additional 2-3% savings by anticipating shifts based on terrain.
- Fatigue reduction: On a 600 km journey, a driver with a manual gearbox makes between 1,500 and 2,000 gear changes. With AMT, zero. This significantly reduces muscular fatigue and cognitive load, especially in dense urban traffic.
- Lower maintenance costs: The clutch lasts longer because shifts are always executed at the optimal engine speed. Typical clutch life with AMT is 500,000-800,000 km versus 200,000-400,000 km with manual.
- Multi-driver fleets: In fleets where several drivers share the same vehicle, AMT ensures a uniform driving style, preventing clutch abuse and incorrect shifts that shorten powertrain life.
- Driver recruitment: The shortage of professional drivers in Europe makes AMT a requirement to attract new drivers, many of whom have never driven with a manual clutch.
