There will be a label on top of the radiator. You may need to do some dis-assembly to find it. It will specify the manufacturer as well as the production date. This is the first thing you should do. If you already have the improved radiator, the ETC.6 control module is the likely culprit.

Now, if it turns out that you do have a coolant contamination problem, I wouldn't worry too much about subsequent damage. Replacing the radiator, and completely flushing the transmission fixes the problem almost all the time. Over the last two years or so, I've had to replace two torque converters (by the way, it's the clutches in the T.C. that cause the "bump/jump" when shifting) to completely eliminate the problem, but I've had dozens that were fixed by flushing.

My advice is to go to your dealer and ask to road test the car with a Shop Foreman. That way you'll know if your car does indeed have the problem I think it does. If you opt to go to an independant shop, or a transmission shop, ask them if they're familiar with the issue first. If they look at you funny run, don't walk, to an MB dealer. Good luck, and let us know what happens.