HYDAC transmission valves Custom valve technology for your transmission application

Are you looking for a way to set your transmission applications apart from your competitors with better performance? You're not alone: the requirements for the "valve" component are always increasing. Special and system solutions are high priority matters.

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Topics & Products Control technology

Uniform control logic - versatile challengesHYDAC – your specialist partner for application-specific valve technology

HYDAC's precision-fit valve solutions for controlling powershift and dual clutch transmissions enable you to effectively improve performance. As a result of many years of experience, we are able to offer you an extensive product portfolio of proportional and hydromechanical valves for a wide range of transmission purposes. Using a collaborative and innovative approach, we provide you with solutions for the specific valve technology challenges that arise in transmission applications.

Advanced transmission technology adapted to your application

Looking for a transmission offering reliable, repeatable, dynamic and precise performance? We have the right valve for each transmission element. This enables controllable, precise and dynamic gear changes during clutch or transmission brake control. Extensive testing ensures continuous optimisation – with HYDAC transmission valves, the oil's susceptibility to contamination and leakages are both reduced to a minimum. In addition, our valves are also optimised for cold-start performance.

Alongside key functional criteria such as switching time, pressure loss and hysteresis, we also focus on integrability, commissioning and reducing the installation space required. Our compact yet robust designs with high power density meet all of these challenges. To facilitate commissioning, we also offer the provision of individual valve measurement data via QR code.

Innovative - compact - robust Explore our transmission valve solutions

Proportional pressure reducing valves for high-volume flow requirements

The large cross sections of HYDAC valves ensure there is only minimal pressure loss when loading /unloading the clutch. The ratio of nominal flow rate to required installation space is impressive. Both our direct acting and pilot operated valves are extremely low leakage. HYDAC offers different pressure ranges for improved inching and consistent switching.


  • Pilot operated
  • Significantly reduced loss through leakage due to patented pilot oil shut-off in de-energised state
  • Unrivalled compact design


  • Direct acting
  • A compact solenoid design proportional to the nominal flow rate enables dynamic switching characteristics due to low inductance

Proportional pressure reducing valves for powershift transmission

The use of smaller direct acting valves ensures controlled filling of the clutch through control of the flow rate. Our valves therefore enable a repeatable, consistent clutch filling process. The linear, slightly falling pressure control characteristic guarantees a smooth application of the clutch discs, and, as a result, the configured switching characteristics.

PDMC05S30A-50 and PDR08-50

  • Only very minimal pressure losses when the connection is relieved due to adapted terminal connection


  • A compact solenoid design proportional to the nominal flow rate enables dynamic switching characteristics due to low inductance

Proportional pressure reducing valves with inverse performance curve

The inverse performance curve ensures that maximum clutch pressure is maintained in the event of a fault, e.g. a cable break.


  • Pilot operated solution for high flow rates
  • At maximum current speed, pressure can be reduced to zero


  • Direct acting solution for lower flow rates
  • At maximum current speed, pressure can be reduced to zero

3/2 directional valves for s/w clutch control

Compact valves with high power density can be used as an alternative to a proportional pressure reducing valve in the same installation space.


  • Significantly simplified switching functions

Pressure relief valves; mechanical and electrical

HYDAC pressure relief valves provide a consistent system pressure across the entire flow range. Both hydromechanical and proportional valve versions are available here. All valves have a separate vent port that enables the gear hydraulics to be supplied with pressure without being affected by back pressure.


  • Direct acting, hydromechanical pressure relief valve
  • Optimal contamination resistance
  • Accurate default setting of the system pressure
  • Stable control performance
  • Good cold-start performance

DB10SPE / DBM12121PE

  • Pilot operated hydromechanical pressure relief valve
  • Extremely compact design


  • Electrically actuated system pressure supply with fixed setting
  • Increased efficiency through switch-off of transmission hydraulics when idle


  • Infinitely variable adjustment of system pressure
  • Temporary boost of system pressure for increased torque transmission
  • Increased efficiency through switch-off of transmission hydraulics when idle via fail-safe function

Your advantages at a glance


Comprehensive valve know-how

Thanks to many years of experience in the application of transmission valves, HYDAC is your specialist partner for custom designed valve solutions.


Optimised design

We place great emphasis on integrability, commissioning and reducing installation space – HYDAC transmission valves are characterised by their extremely compact design and high power density. 

Tailor-made solution

A perfect fit

HYDAC's product portfolio ensures the perfect valve for countless functions and their associated requirements.

Technological challenges

Solutions for the challenges you face

Severe contamination, increased viscosity, the presence of air in the oil or harsh environmental conditions – let's talk about it. HYDAC is adept at selecting the right valve for your requirement.

Contact us for advice!

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