Automatic transmission flushing units

Frequently Asked Questions About Automatic Transmission Flushing Machines

Transmission oil changes and transmission flushing are different service procedures and must be tailored to the specific automatic transmission. In addition to using the correct oil, the connection point, oil temperature, fluid level, and manufacturer’s specifications are particularly important. Here, we answer frequently asked questions about professional automatic transmission flushing and the use of transmission oil flushing equipment.

• What is an automatic transmission flush?

  During an automatic transmission flush, transmission fluid is circulated through the transmission’s oil system, and the existing used fluid is systematically replaced with suitable fresh fluid.
  
  Depending on the transmission and the procedure, this process may also include areas of the oil system from which not all of the fluid is drained during a simple drain.
  
  Whether a flush is recommended or permitted depends on the specifications of the respective vehicle or transmission manufacturer.

• What is the difference between a transmission oil change and a transmission flush?

  During a standard transmission oil change, the oil that drains out through the designated drain point is replaced.

  Depending on the transmission design, used oil may remain in, among other places:

  • the torque converter
  • lines
  • heat exchangers
  • the hydraulic unit
  • other areas of the transmission.

  During a transmission flush, additional oil is circulated through the system, and the used oil is systematically replaced with fresh oil.

• Is a transmission flush generally better than a regular oil change?

  No, not across the board.
  
  The key factor is which maintenance procedure the vehicle or transmission manufacturer specifies for that particular transmission.
  
  Depending on the transmission, a standard oil change, a flush, or another service procedure may be recommended.

• Can any automatic transmission be flushed?

  Not automatically.

  Before using a flushing device, the following must be checked, among other things:

  • Transmission type
  • Manufacturer approvals or service specifications
  • Transmission condition
  • Required adapters
  • Specified transmission fluid
  • Filling and oil level procedures

  The technical ability to connect an adapter does not automatically mean that flushing is intended for the transmission in question.

• Which gearboxes can be machined using Leitenberger AGSG machines?

  AGSG units are designed for various types of automatic transmissions.

  These include:

  • Torque converter automatic transmissions
  • Continuously variable automatic transmissions (CVT)
  • Dual-clutch transmissions (DSG/DCT)

  The specific application depends on the transmission, the vehicle, and the available adapters.

• Can the AGSG be used just for a transmission oil change?

  Yes.
  
  The unit can be used for both oil changes and flushing.
  
  This allows the workshop workflow to be adapted to the service procedure specified for the respective transmission.

• What is the transmission fluid change interval for the AGSG?

  Leitenberger specifies a gear oil replacement rate of at least 95 percent for the AGSG using the intended flushing procedure.
  
  This specification refers to this specific unit and its intended flushing process.
  
  It should not be interpreted as a general statement applicable to every flushing unit or every transmission.

• Is the automatic transmission flushing machine electric?

  Yes.
  
  The current Leitenberger AGSG devices are powered by 12 VDC.
  
  This makes it easy to provide the necessary power supply during workshop operations.

• Can a cleaner be used during the transmission flush?

  The AGSG allows the flushing and cleaning process to be performed with or without an additive or cleaner, depending on the intended procedure.
  
  However, whether a cleaner may be used with a specific transmission must be verified based on the relevant service and manufacturer information.

• Can using the wrong transmission fluid be corrected by flushing the transmission?

  If the wrong or unsuitable oil has been added, the first step is to determine which service procedure the transmission manufacturer recommends in this case.

  Flushing should not automatically be considered a universal solution.

  The following factors are crucial:

  • incorrect fluid used
  • specified oil
  • duration or operating time
  • condition of the transmission
  • manufacturer’s specifications
• Can a transmission flush repair a mechanically defective transmission?

  No.

  A flush is a maintenance procedure, not a repair for mechanically damaged components.

  Jerking, gearshift shocks, slippage, or noises can have various causes, such as:

  • Oil condition or oil level
  • Hydraulic problems
  • Wear
  • Clutches
  • Valve body or mechatronics
  • Sensors or electronics

  Therefore, if these symptoms are present, a systematic diagnosis should be performed before any extensive service work is carried out.

• Why is using the right transmission fluid especially important during a flush?

  During a flush, a large volume of oil is circulated through the system or replaced.

  The oil used must therefore precisely meet the transmission’s specified requirements.

  Different ATF and transmission oils may differ in terms of, among other things:

  • Viscosity
  • Friction coefficients
  • Additive composition
  • Material compatibility
  • Manufacturer approvals.
• Why are different adapters needed for transmission flushing machines?

  The connection to the transmission oil circuit varies depending on the vehicle and transmission manufacturers.

  Differences exist, for example, in:

  • Hose connections
  • Heat exchangers
  • Screw connections
  • Couplings
  • Connection locations

  That is why Leitenberger offers various adapters for automatic transmission flushing units.

• Are there adapter kits available for specific automakers?

  Yes.

  AGSG offers, among other things, pre-assembled adapter kits for various manufacturers and applications.

  These include, for example, solutions for:

  • BMW
  • Mercedes-Benz
  • VW/Audi

  In addition, numerous individual adapters are available for various transmission manufacturers and systems.

• How can I tell if the supply and return lines are connected correctly?

  On the Leitenberger AGSG, a visual oil flow indicator allows the flow direction to be checked.
  
  This makes it possible to verify, either before or during service, whether the oil circuit has been correctly integrated into the test setup.

• Can the transmission oil pressure and temperature be displayed during service?

  An additional pressure and temperature gauge is available for the AGSG.
  
  This allows the pressure and temperature of the circulating gear oil to be displayed during an oil change or service procedure.
  
  The gear oil temperature can be particularly important for correctly setting the oil level afterward.

• Why is the transmission oil temperature important during filling?

  In many automatic transmissions, the correct oil level is set within a defined temperature range.
  
  Transmission fluid changes volume with temperature.
  
  Therefore, oil level checks and filling procedures must be performed in accordance with the specific instructions provided by the vehicle or transmission manufacturer.

• Can the AGSG be used with different types of transmission fluid?

  Yes, provided the unit is properly prepared and the oils used are suitable for the specific vehicle application.
  
  Additional fresh oil canisters are available for the AGSG.
  
  This can simplify the handling of different transmission oils in a workshop setting.
  
  Mixing incompatible oils must be avoided.

• Can the AGSG also be used as a filling station?

  Yes.

  The Leitenberg service station is also designed for filling operations.

  For filling tasks involving various types of transmissions, transmission oil filling pumps and filling adapters are also available.

• Should the transmission fluid be checked before flushing?

  A visual inspection or condition check may be useful as part of the diagnostic process.

  If internal mixing with coolant is suspected, a transmission fluid tester for detecting coolant can also be used.

  Such a test is particularly useful when a defect in the transmission fluid heat exchanger is suspected.

• Can the transmission oil pressure be checked before flushing?

  If the symptoms indicate a problem, a mechanical pressure measurement may be helpful.

  Using an automatic transmission oil pressure tester, you can check the actual hydraulic pressure at a designated measurement point.

  This can help distinguish between routine oil service and actual transmission diagnostics.

• What should be checked after flushing the transmission?

  Depending on the transmission, the following tasks may be required in particular:

  • Set the specified oil level
  • Take the oil temperature into account
  • Check the system for leaks
  • Check for error codes
  • Perform adaptation or service functions as needed
  • Test drive or functional test

  The exact procedure depends on the manufacturer’s specifications.

  You can find additional solutions under Test and Service Equipment for Transmissions and Transmission Fluid.