The RPM seems to go higher (close to red) and seems not to go to the next gear?

Thank you very much for that bit of information, I will have the transmission fluid checked. The funny thing now is that it's working normal (since the problem occurred yesterday) but now the check engine light is on. I had to replace the battery in the key and from what I saw on you tube videos, they informed that you have to reset the computer system in the car but I think I will check on yelp for shops that specialize in Mercedes out here in San Diego. Thanks again for your response!