Guide To Differentiating Between The 722.6, W5A580, & NAG1 Mercedes Transmission

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It can be a bit confusing when discussing 5G-Tronic automatic transmissions. The model W5A 580, type 722.6, was also called the NAG 1, which stands for the New Automatic Gearbox Generation One. The NAG1 term is most frequently used when referring to cars made by Daimer-Chrysler.

The W5A 580 refers to the classification of the transmission. The numbers 722.6 refer to the type of transmission, basically the name of it. NAG1 is just another name for the transmission.

This particular transmission was used in various models of Mercedes, Daimler, Porsche, and Jaguars, according to Transmission Digest. Its popularity was due to the fact that the transmission was reliable, and in many cases, if repairs were required, they were easy to fix. 

The unique thing about these Mercedes transmissions is that it has a “locked” transmission fluted receptacle. It was created with the proper amount of transmission fluid. If repairs were required on the transmission, a special tool and fluid would be required to tackle the task. This meant that the repairs needed to be done by a qualified service technician.


Transmissions: 722.6 Transmission Developed by Mercedes:

The 722.6 transmissions have been a workhouse for the company. It was first manufactured in 1996 and used for many years. It is still available on the market, though now most options are rebuilt.

The 5G-Tronic transmission replaced the 4G-Tronic, which was just a 4-speed. The new 5G-Tronic was more complex, offering higher torque capacity and a torque converter lock-up. The 5G-Tronic 722.6 transmission (or NAG 1) has five forward speeds and two backward speeds.

The 722.6 transmissions were designated 5WA(XXX), and the XXX designated the maximum input torque that the transmission would be able to convert safely which was 580. Hence the W5A580 transmission.

After 2000, the model was upgraded, and changes were made to the valve, various mechanical parts, and internal details. Additional changes were subtly made to the transmission throughout the years, and today the 722.6 has had numerous upgrades, going from the first 722.6 versions to 722.699. Each new version added a number to the identity of the part.


Issues with the 722.6 Transmission:

While this is a great transmission and is used in numerous model vehicles, no part is without some issues. The good news is the 722.6 transmission is a well-built and reliable transmission model. In most cases, it is easy to repair.

Here are some of the more common issues found in the 722.6 model transmissions according to

  • Leaks at the plug adapter: The plug adapter has three o-rings, these rings are known to leak, and when they do, the connectors’ tabs typically will leak as well.
  • Poor conductor plate design: Some early models have poorly designed valve conductor plates which often lead to poor starting. If the part needs to be replaced the valve body will need to be removed but can be fixed with the transmission in the vehicle.
  • Module malfunction:  The 722.6 has an issue with the transmission fluid going into the control module, causing it to malfunction. In most cases the harness and ETC model are replaced, resolving the leak problem.