Turbo Retarder Clutch

The Turbo Retarder Clutch VIAB is a completely new start-up and braking system

With a fill-regulated, hydrodynamic fluid coupling as the main component, it unites the hydrodynamic start-up and hydrodynamic braking functions into one system.

Handling heavy transporters made easy:
The Turbo Retarder Clutch VIAB

Powerful start-up and safe braking - with no wear and for loads up to 250 tons. With the Turbo Retarder Clutch (from the German: Wear-free Integrated Starting and Braking system), two elements that appear to be mutually exclusive work together: The advantages of hydrodynamics when starting and braking with the high efficiencies of a mechanical driveline while driving.

Stress and tension behind the wheel? Not anymore. VIAB scores high when it comes to sensitive start-up and braking behaviour, as well as driving comfort. Just put your foot on the metal. As usual, simply pull the lever and the retarder decelerates safety and without wear. As many times as you like. Forget about overheating problems and all the other disadvantages of traditional torque converter solutions.

Experience it for yourself: The Turbo Retarder Clutch VIAB is a standard feature in the Mercedes Benz Actros SLT.

Powerful start-up and safe braking - with no wear and for loads up to 250 tons.


VIAB is the smart choice for vehicles that

  • require a high-performance retarder even at low-velocity
  • start frequently and have long maneuvering times
  • transport heavy goods

Common applications include

  • timber transporters
  • construction machinery transporters
  • milk collectors
  • mobile cranes


The benefits to you

  • High comfort through sensitive hydrodynamic start-up and shifting
  • High availability thanks to a wear-free start-up without friction coupling
  • Integrated high performance primary retarder
  • Maximum start-up tractive power at low speeds
  • Full conversion of engine torque up to traction limit
  • Overload-resistant with high thermal stability
  • Lower fuel consumption in comparison to conventional converter solutions
  • New efficient automatic transmission concept: combination of turbo coupling and automated manual transmission

Benefits for end users

  • High comfort due to sensitive, hydrodynamic starting and maneuvering
  • Wear-free transmission of torque and thermal stability ensure maximum vehicle availability, even with heavy loads, frequent starts, long periods of maneuvering or extremely low velocity
  • Maximum starting tractive effort even at low engine speeds
  • Full utilization of engine torque up to traction limit
  • Lower fuel consumption compared with conventional converter solutions
  • Integrated powerful retarder
  • Primary retarder allows maximum braking power even at low velocity
  • Retarder function also in reverse gear

Advantages for vehicle manufacturers

  • Starting behavior can be optimally adapted to engine characteristics
  • One VIAB model suits different engine versions
  • Input torque up to over 3 000 Nm
  • Starting and braking with the same hydrodynamic circuit
  • Low weight, low installation space requirements
  • New, effi cient automatic transmission concept in combination with automated manual transmission

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Principle of operation

Principle of operation diagram

Turbokupplung Funktionsschema

ÜK Converter lockup clutch
D Torsional vibration damper
TK Fluid coupling
P Impeller
T Turbine wheel
R Rotor
S Stator
F Free wheel coupling
TB Turbine brakes

Upon start-up, the motor transfers power via the hydrodynamic circuit, as well as the downstream free wheel, to the transmission input shaft. Parallel to the circuit, a conventional friction coupling is arranged as a converter coupling.

When braking, the turbine brake arrests the turbine wheel. The system turns into a high performing retarder.

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Turbo Retarder Clutch
VIAB - Trucks

Voith Turbo GmbH & Co. KG
Commercial Vehicles
Alexanderstraße 2
89522 Heidenheim, Germany

Mercedes-Benz Roadstars-Movie

The wear-free Turbo Retarder Clutch combines the functions of a hydrodynamic start-up clutch and a primary retarder in a single component...

Mercedes-Benz Roadstars-Film

The wear-free Turbo Retarder Clutch combines the functions of a hydrodynamic start-up clutch and a primary retarder in a single component..


Technical Support
Tel. +49 7951/32-1555

Spare parts orders
Tel. +49 7951/32-1644
Fax +49 7951/32-574

Ms Sabrina Lipok:
Tel. +49 5341 21 5446
Mr Sascha Koch:
Tel. +49 5341 21 4872


Turbo Retarder Clutch VIAB

Turbo Retarder Clutch VIAB

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