Originally posted by Phalcon51
If you really did drain the trans (the fluid would be red), you'll have to pour in as much as you drained. If possible, fill until it just registers at the lower mark.
Gary, can you verify that the lower tick mark is the appropriate mark to reference for cold fluid in a C230? If not...
If you don't know how much transmission fluid you drained, fill in half quart increments until you get to 10mm below the lower tick mark on the dipstick. That should be enough fluid to get the car running (once the engine oil issue is resolved). From this point, fill only with the engine running and the transmission fluid at operating temperature. That means drive the car. The transmission doesn't get to operating temperature by idling the engine.
Why? Some MB transmissions are spec'd to register as much as 12mm below the lower tick mark when the fluid is cold. It doesn't take long to blow seals with too much fluid whereas a transmission will go for quite a while with too little fluid.
Out of curiosity, what tool did you use to remove the plug to drain oil - a wrench or conventional socket, or a hex bit socket or allen key?