Good morning, inorder to check the fluid you will need the special tool......there is no dipstick in the tube of this vehicle. Give it to the germans to not allow anyone other then those with the special tool to check it. I believe the main reason why its not in the vehicle is because it also requires a scanner to check the trans temp. The correct level is based on trans temp and the reading on the special tool. Here is a picture of the special tools:
The part number for the tools is 8863b.
You can order the part from Miller tools and it cost around $58.00:
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