In this guide, you will find instructions on how to check the transmission fluid level on Mercedes-Benz 722.9 transmission also known as 7G-Tronic or NAG2.

There is no dipstick on the 722.9 that will allow you to check the transmission fluid level. On the 7-speed transmission, you check fluid level using the overflow method.

Inside the transmission pan, there is an overflow pipe on top of the drain plug. The height of this pipe is used to ensure the correct transmission fluid level.

What you will need

Procedure

Checking transmission fluid level requires transmission to be at a precise temperature, take your car for a short 10-minute drive to warm it up. 

  1. Raise the vehicle at all four-wheels and make sure the vehicle is level.raise vehicle to check transmisison fluid level on 722.9 7 speed transmissionThe easiest way to do this is on a lift. If you don’t have access to a lift, lift both the front and rear side of the car up. Secure the vehicle on jack stands, making sure it is leveled and sits securely.
  2. Remove the whole splash guard under the transmission.splash shield need to be removed to check mercedes transmission fluid levelsplash guard under transmissionYou will need an 8mm socket to remove the screws.remove screws

     

  3. Locate the drain plug at the bottom of the transmission pan.oil drain plugBreak it free using a 6mm Allen key, but don’t remove it just yet. 722.9 oil level measuring plug

     

  4. Position a drain pan underneath the drain plug.
  5. Climb into the car, turn on the engine and check the transmission temperature using an  IR thermometer by pointing it at the transmission oil pan. You can check the transmission oil temperature with an advanced diagnostic scanner as well. 
  6. With transmission temperature at 45 °C, push the gearbox lever through P-R-D and back several times. 
  7. Go back underneath the car and remove the drain plug.check oil level 722.9 7 speed transmisisonCarefully observe what happens.
      - If nothing flows out - fluid level is too low - go to step 9
      - If there is a strong and continuous flow - fluid level is too high - skip to step 12
      - If oil drips in small quantities - fluid level is correct - skip to step 13
  8. If the transmission fluid level is low, fill the transfer pump with 1 liter of transmission fluid. 
  9. Place the filler adapter into the drain plug, connect the pump hose on it and open the valve. Pump about 0,5 quarts and then close the valve. 
  10. Disconnect the filler adapter allow excess fluid to drain until only a small amount still drains out. If there is no transmission fluid draining out add more and repeat the process as needed.
  11. Wait until the excess transmission fluid drains until the flow is very weak. 
  12. Reinstall the transmission drain plug and tighten it to 17 lb-ft using a torque wrench 
  13. Reinstall all remaining parts. 
     

Most Mercedes cars made after 2005 use a 7-speed automatic transmission, called 7G-Tronic or NAG2. The 722.9 transmissions were installed in European vehicles around 2000 while in the US it was installed on most 2005 and newer models.

Mercedes-Benz 7-speed transmission is a superb gearbox that offers improved performance, shorter shift times and improved fuel economy.

Many car owners find that checking the transmission fluid level inside this transmission to be troublesome, as there is no dipstick.

Application 

Mercedes-Benz 722.9 transmission was available in a few different US models as early as 2004 which in Europe was available in the C-Class as early as 2000.

  • SLK (R171 starting in 09/04
  • M Class W164 starting in 2005
  • R Class W251 staring in 2005
  • G Class X164 starting in 2006
  • CLS 350 / 500 starting in  2004
  • E Class starting in 2004

722.9 became the standard transmission for various chassis including 164, 171, 203, 204, 207, 209, 211, 212, 215, 216, 219, 220, 221, 230, 251, 463. 

4Matic equipped vehicles were the last models to phase out the 722.6 and shift to 722.9 around 2006-2007.

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