Economy and environment in focus: DIWA automatic transmissions for buses
Accelerate, shift, brake, shift. City bus operators face numerous challenges on the road each day. As a bus manufacturer or operator, rely on Voith’s globally successful DIWA automatic transmissions. With DIWA, you can benefit from intelligent shifting and reduced downtime, maintenance costs and fuel usage.
Today, over 400,000 city and intercity buses worldwide use a DIWA automatic transmission. Millions of passengers enjoy a more comfortable ride with less noise. At speeds that require other transmissions to shift two to three times, Voith offers you the benefit of stepless accelerating and braking.
Your benefits
- Lower fuel consumption
- Reduced air and noise pollution
- Maximum comfort for passengers
- Low maintenance costs
- Lower installation effort
- Global market leader in CNG buses
- Meets the needs of demanding BRT systems worldwide
The right transmission.
At the right time.
DIWA NXT
DIWA NXT is the consistent response to the growing demand for environmentally friendly drive solutions. Thanks to its hybrid system, the automatic transmission closes the gap to alternative drive systems and achieves fuel savings of up to 16%. DIWA NXT offers fleet operators and drivers a wide range of options in a solution that is efficient, comfortable and quiet.
DIWA NXT: Automatic transmission for all bus operation
DIWA NXT is the next generation transmission for city and regional busses and coaches. It is optimized in terms of efficiency with a 2nd overdrive, a separate retarder and an optional Central Recuperation Unit (CRU) based on 48V technology to keep fuel consumption as low as possible.
The DIWA NXT is a mild hybrid system with various advantages. It is highly integrated into the flywheel housing of the engine and works with a specifically developed inverter, which is located on the top of the transmission to avoid line losses. A specifically designed battery and cooling system including an optimized DC/DC converter is available. The 48V mild hybrid system is developed specifically for buses and carries out various functions like stop-start, coasting, recuperation during braking procedures or even boosting-support. The new DIWA NXT is one of Voiths answers on the increasing demand for efficient and green driveline technologies and helps to bridge the gap between Diesel and alternative drivetrain technologies.
- World-premiere: performance of differential converter and retarder can now be independently optimized
- Recuperates braking energy based on a highly-integrated 48V mild-hybrid system
- Reduces fuel consumption by up to 16%
- Reduces air and noise pollution
- Seamless hardware-software integration from one provider: Voith Digital Ventures

Demo bus takes to the road on scheduled service
Success Story DIWA NXT
SUCCESS STORY DIWA NXT: DEMO BUS TAKES TO ROAD ON SCHEDULED SERVICE
Our solution to increasing demand for new drive concepts
With its mild hybrid system, the latest generation of our DIWA automatic transmission is closing the gap between diesel-only systems and other alternative drive technologies. And demand for these kinds of solutions above and beyond the pure internal combustion engine is steadily increasing. The reason for this is that to make further progress in reducing CO2, bus operators need to restructure their fleets substantially in the next few years.
Multi-week testing phase at OK.go
As far as emissions are concerned, the existing engine concepts have largely reached their limits. At OK.go, a regional bus company whose services are an important component of the public transport system in the Ostalbkreis district on the outskirts of Stuttgart, the decision-making process for the switch is also already well underway. The multi-week testing phase of our demo bus, a combination of Iveco Crossway and our DIWA NXT, is an important part of this journey towards more sustainability.
For economic reasons too, it makes sense to store the energy produced during braking and decelerating. The electrical energy can then be used for pulling off and to supply the vehicle electrical system. This reduces fuel consumption as a result.
As far as emissions are concerned, the existing engine concepts have largely reached their limits. At OK.go, a regional bus company whose services are an important component of the public transport system in the Ostalbkreis district on the outskirts of Stuttgart, the decision-making process for the switch is also already well underway. The multi-week testing phase of our demo bus, a combination of Iveco Crossway and our DIWA NXT, is an important part of this journey towards more sustainability.
DIWA.6 automatic transmission
Whatever your requirements as a bus manufacturer or operator, with Voith you’ll find a suitable DIWA automatic transmission that lowers your fuel consumption and decreases your carbon footprint.
Destination: 100% economical – DIWA.6
The DIWA.6 automatic transmission is the global standard for economically advantageous and sustainable city and intercity buses.
Together, intelligent acceleration management and need-based reduction of operating pressure reduce fuel consumption.
As a bus manufacturer or city bus operator, you profit from a dramatic increase in the transmission’s efficiency.

Your benefits at a glance
- Optimized fuel-efficiency
- Lower air and noise pollution
- Maximum passenger comfort and safety
- Tried and true stop-start technology
- Lower maintenance and installation costs
- High degree of reliability and availability
Stop-start technology for DIWA.6
Better for the environment:
Our stop-start technology for your DIWA.6 transmission
City buses spend up to 40% of their operating time in idle mode. Tried and tested worldwide, Voith’s stop-start technology uses this downtime to greatly reduce fuel consumption and emissions. Do your part to combat climate change while making public transportation more attractive.
- Proven in operation in more than 1,500 buses
- Reduces fuel consumption by up to 12 %
- Reduces air and noise pollution
- Greater riding comfort for drivers, passengers, pedestrians and residents
- Software for easy updates
Functional principle DIWA automatic transmission
Our Service - Part of Your Business
- Everything from a single source: development, design, production – and service!
- Decades of product experience as an original equipment manufacturer and service provider
- Fast and smooth cooperation and best service thanks to a worldwide network of service locations
- Long-term partnership and planning security are guaranteed due to longstanding corporate stability
Questions? We are here to help.
International DIWA references
Worldwide, bus operators large and small value the fuel savings made possible by Voith’s innovative DIWA transmissions. These transmissions have the ability to flexibly adapt to a range of infrastructure and topography specifications, which makes them usable in almost any market. This is especially true in emerging markets such as Africa, where the demand for public transportation is continually rising.

DIWA in bus rapid transit systems (BRT)
– Market share Voith: 84 %
Since TransMilenio’s launch, driving times have dropped by 32% and emissions by 40%. The TransMilenio BRT system transports around 2 million passengers each day, making it one of the most efficient BRT systems worldwide. Today TransMilenio is considered a benchmark for many cities worldwide looking to introduce a BRT system.
Voith is a CNG-powered bus leader
Environmentally-friendly operations in North America
Establishing a modern transportation system in Baku, Azerbaijan
Further quality power train products from Voith
The perfect drive system for changing intra-urban mobility: As an established system supplier with many years of experience and a partner to the bus industry, we have combined our comprehensive know-how in the fields of drive systems and E-mobility. Voith has developed a pioneering electrical drive system for local public transit. The Voith Electrical Drive System (VEDS).
Learn more