Modern city bus driving on deserted new street in desert-like environment
Automatic Transmissions – Bus

DIWA automatic transmissions for city and intercity buses

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 50% less shifting and reduced downtime, maintenance costs and fuel usage.

    Today, over 300,000 midsize, 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.

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    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

    Driven by Efficiency

      DIWA NXT: Automatic transmission for all bus operation

        DIWA NXT transmission with central recuperation unit

        DIWA NXT is the next generation transmission for city, suburban and coach buses. 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

        DIWA.6 und DIWA.5 automatic transmission

          Two modern red double-decker buses at a bus stop

          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 by up to 5%.
          As a bus manufacturer or city bus operator, you profit from a dramatic increase in the transmission’s efficiency.

          Cross section of DIWA.6 automatic transmission

          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


          Megacity or intercity – DIWA.5 advances efficiently

          Cross section of DIWA.5 automatic transmission
          No matter what corner of the globe your city buses are traversing, the intelligent DIWA.5 automatic transmission adapts to the given requirements. Count on buses with low maintenance and operating costs and high availability. 

          As a bus manufacturer, choose the compact DIWA.5 without external pipes or tubes, and easily install it in the most confined spaces.

          Your benefits at a glance

          • Great value
          • Low wear
          • Enhanced comfort for passengers and drivers
          • Reduced thermal load of the cooling circuit


          DIWA product features

            Functional principle DIWA automatic transmission

            Voith automatic transmission for buses - Comparison scheme of the DIWA functional principle
            Specially developed for public transit buses, these transmissions are a must-have for economical operation: Reduced complexity and less installation effort for the manufacturer, lower fuel consumption and rock-bottom maintenance and service costs for the operator. And not only today - but for the entire service life of the bus.
            Learn more about how it works in our detailed videos

            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



            For operation managers in local puplic transport who have to reduce operational cost (fuel consumption as a major cost driver), our OnEfficiency.SmartAccelerate is a software configuration upgrade for your DIWA transmission, which helps to reduce significantly and sustainably fuel consumption.

            LEARN MORE ABOUT OnEfficiency.SmartAccelerate

            DIWA EfficiencyPro

            Modern covered bus depot in Asia with long line of buses

            The intelligent path to even lower fuel consumption

            Voith is always coming up with new ideas: DIWA EfficiencyPro is a software enhancement that enables eco-friendlier driving and lowers fuel consumption. City bus operators can instantly experience additional fuel savings of up to 4%.

            E300.1/E310 Control Unit

            Voith’s family of transmission control units represents in-house developments that don’t just fulfill the latest automotive standards, but also perfectly meet Voith’s vigorous requirements for automatic transmissions in city buses. Processing power and memory are perfectly balanced against great value and performance. The tilt sensor captures the grade of the road, laying the foundation for the topography-dependent shifting program, SensoTop.
            Beyond connecting to the vehicle, multiple interfaces link to electronic type plates installed in the transmission. Diagnostic interfaces grant access to the control unit via a diagnostic tester and a telematic control unit (TCU) to transmit data remotely.

            The TCU’s software is also developed in-house at Voith. It upholds the highest security standards and protects the unique DIWA function our customers look for.


            The topography-dependent shifting program continually evaluates all key information from the control unit, such as acceleration, load, grade of the road, and dynamically determines the optimum time to shift.

            SensoTop’s abilities have been proven in countless applications worldwide. Depending on topography and vehicle application, real-life potential for fuel savings have been up to 7% compared to an optimized, acceleration-dependent shifting program.
            This leads to a noticeable drop in operating costs. SensoTop also actively helps protect the environment by reducing carbon and particulate matter emissions.

            Service products


            The tried and tested diagnostic tool for all DIWA generations enables detailed diagnostics of the transmission and its components. Error data can be read out, and operating data analyzed and interpreted. This aids optimization and power train design.


            This telemetry solution is for bus fleet operators seeking to lower the TOC and downtime of their fleet, with minimal effort.

            The system transmits the latest status data to responsible parties, keeping fleets up and running according to the health of the components.


            For operation managers in local puplic transport who have to reduce operational cost (fuel consumption as a major cost driver), our OnEfficiency.SmartAccelerate is a software configuration upgrade for your DIWA transmission, which helps to reduce significantly and sustainably fuel consumption.

            LEARN MORE ABOUT OnEfficiency.SmartAccelerate

            Questions? We are here to help.

              Contact our experts

              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.

                Current distribution of the 160,000 DIWA transmissions used worldwide
                A world map showing distribution of the 150,000 DIWA automatic transmissions used worldwide today
                Nicholas de la Rosa
                In my 17 years at Manatee County Fleet Services Division, Voith's DIWA transmission for buses have proven themselves time and again. They are just incredibly durable. We've always had great support from Voith, too. These transmissions are well worth the investment.
                Nicholas de la Rosa, Fleet Maintenance Superintendent, Manatee County Fleet Services Division

                DIWA in bus rapid transit systems (BRT)

                  Two red BRT buses driving in separate lanes in Bogotá
                  TransMilenio, Bogotá, Columbia
                  – 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.

                  Multiple buses stopped at a BRT operation in Brisbane in separate lanes in a large bus depot
                  Brisbane Busway in Australia
                  – Market share Voith: 63 %

                  The Brisbane Busway BRT system exemplifies how DIWA transmissions and services, as part of DIWA Excellence, increase driver comfort and overall safety. Using CNG (natural gas) also helps considerably reduced emissions from the start.

                  A modern red articulated bus on a street. The background shows an ultra-modern glass office building.
                  Hangzhou BRT in China
                  – Market share Voith: 89 %

                  In Hangzhou, a service and maintenance contract with predictive maintenance ensures maximum availability and cost transparency for the operator and stakeholders. Driving time is reduced by 40%. Separate bus lanes dramatically help reduce the number of traffic accidents. Based on these findings, Hangzhou has expanded its BRT system to include two additional bus lines.

                  A modern red bus in a separate lane. The background shows a modern high-rise.
                  Zhengzhou BRT in China
                  – Market share Voith: 100 %

                  The integrated DIWA SmartNet concept used in the Zhengzhou BRT system enables predictive maintenance and analysis of operating data in real time. Complete integration of Voith’s ECU data in the operator’s fleet management system considerably reduces system complexity.

                  Voith is a CNG-powered bus leader

                    Bus at a natural gas station

                    Environmentally-friendly operations in North America

                    When phase two of the GHG regulations went into effect with the aim of reducing greenhouse gases in North American cities, there was a clear uptick in demand for climate-friendly CNG systems. Today, over 400 DIWA.6 transmissions are used in CNG engines throughout North America – a number that keeps on growing.
                    A row of modern new buses

                    Establishing a modern transportation system in Baku, Azerbaijan

                    For the first European games in Baku in 2015, 300 new buses to transport fans were equipped with Voith’s DIWA.5 and DIWA.6 automatic transmissions. This marked the start of the city’s modern public transportation system. 

                    Our Service - Part of Your Business

                      Made-to-measure service from Voith

                      Our customers benefit from our years of experience in developing and manufacturing key components for buses. Our accomplished bus experts know exactly what’s required for the success of bus manufacturers and operators.

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