Please help! Where can i check, add transmission fluid on MB 2008 C350?

Identify the transmission type. If the transmission has a fluid fill tube without a dipstick, the transmission is a 5-speed 722.6. If the transmission has no tube, it is a 7-speed 722.9. 2. With a 722.9 transmission, it is required to fill the transmission by using the drain in the pan. When the transmission pan is removed and filter replaced, start by adding 4 1/2 quarts and start the engine.