On the passanger side of the motor near the firewall you will see a red cap on the end of a black tube. There should be a black or red lock on it. Break the lock tab off and press the rest of it throught the cap. This is where you can check or fill your transmission. You will need a thin funnel to fill through the fill tube. You however will be unable to check the fluid level without a MB trans dipstick. These do not come with the vehicles and you will probably have to order one if you want one. Keep in mind when checking your fluid level the car should be running at operating temperature.