problem with my mls 320

I have problem with my car when the weather is cold and the car will not move more than 20 m/hr until after 30 mins of driving and 1 hr of warming up . I took it to dealer twice and they told methere is no problem . Please help me

Does the truck not shift? All MB's hold the trans in first for a few seconds longer than normal when it's cold to help bring the trans fluid to operating tempreture. This is done through the ETC (Trans) control module. It could be possable that it is faulty or the problem lies internal of the trans. My recommendation would be to leave the truck at the dealership and allow a tech to drive the vehical for a few days when the weather is cold.