I don't think you have a transmission problem...in fact, short of unbelievably poor maintenance, MB trannys are pretty solid units.
The "bucking" you are experiencing is happening on idle, and has been described by others as a "surging". Search for "surge" or "surging" on this forum.
I have this problem right now on my 300E...usually worse when its warm (almost non-existent when cold). Haven't taken the time to research it much, but I have gotten responses on my threads indicating it could be a bad switch on the transmission shift column sending error codes to the computer. Also, the temperature sensor is a possible cause (hmmm, maybe that's why it's not so prevalent in cold weather).
I will one day get this fixed and post the results to all, but for your situation, I just wanted to point out that your tranny is just fine, and to look elsewhere for the problem...