Need to check your Mercedes-Benz transmission fluid level? Following the procedures below, you will learn how to check the transmission fluid level without any dipstick.
This guide provides instructions on checking the transmission fluid level on Mercedes-Benz 722.9 transmission, also known as 7G-Tronic or NAG2.
No dipstick on the 722.9 will allow you to check the transmission fluid level. On the 7-speed transmission, you check the fluid level using the overflow method. An overflow pipe is on top of the drain plug inside the transmission. The height of this pipe is used to ensure the correct transmission fluid level.
What you will need
- Transmission Fluid ATF 3353
- A001 989 45 03 10
- 722.9 Transmission Adapter
- Drain plug washer 007603012102
- Fluid transfer pump
- Allen key socket set
- Socket wrench
- IR thermometer
- Oil drain pan
- Torque wrench
- Work gloves
- Floor Jack and Jack Stands
Procedure
Checking transmission fluid level requires the transmission to be at a precise temperature; take your car for a 10-minute drive to warm it up.
- Raise the vehicle at all four wheels and make sure the vehicle is level.
The easiest way to do this is on a lift. If you don’t have access to a lift, lift both the car’s front and rear sides. Secure the vehicle on jack stands, ensuring it is leveled and sits securely. - Remove the whole splash guard under the transmission.
You will need an 8mm socket to remove the screws. - Locate the drain plug at the bottom of the transmission pan. Break it free using a 6mm Allen key, but don’t remove it just yet.
- Position a drain pan underneath the drain plug.
- 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 also check the transmission oil temperature with an advanced diagnostic scanner.
- With transmission temperature at 45 °C, push the gearbox lever through P-R-D and back several times.
- Go back underneath the car and remove the drain plug. Carefully observe what happens.
– If nothing flows out – the 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 - If the transmission fluid level is low, fill the transfer pump with 1 liter of transmission fluid.
- Place the filler adapter into the drain plug, connect the pump hose to it, and open the valve. Pump about 0.5 quarts and then close the valve.
- Disconnect the filler adapter and 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.
- Wait until the excess transmission fluid drains until the flow is minimal.
- Reinstall the transmission drain plug and tighten it to 17 lb-ft using a torque wrench
- Reinstall all remaining parts.
The easiest way to do this is on a lift. If you don’t have access to a lift, lift both the car’s front and rear sides. Secure the vehicle on jack stands, ensuring it is leveled and sits securely.
You will need an 8mm socket to remove the screws.
Break it free using a 6mm Allen key, but don’t remove it just yet. 
Carefully observe what happens.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.
The Mercedes-Benz 7-speed transmission is a superb gearbox that offers improved performance, shorter shift times, and fuel economy.
Many car owners find 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.
We hope you find the Mercedes 722.9 7-Speed Transmission – Check Fluid Level guide helpful. Check these troubleshooting and repair guides for more help on your Mercedes-Benz.