I got a 2003 E class 2.7 liter, automatic. So im not still sure if it has 5 or 7 gears but when i want to shift manually by tapping on the shifter it only shows me 4 gears on the screen, and still if i put it on any gear if i accelerate it will stil change gears on its own. I dont understand that sistem

 

Go to the mbepc.net, and type your VIN to there. It'll show which one you have, 722.6 being 5-speed and 722.9 being 7-speed.
I assume you have 5-speed if it only shows 4 gears on cluster, because I have 7-G trans and it shows 6 gears on cluster.

 

03 E270CDI = 722.6 5-speed