This problem has happened to me two times in the past month.
I was doing around 55 and the road was curving slightly when I suddenly saw a large object in the middle of the road. I could not go to the other lane because a car was right next to me so I slammed on the brakes, I felt ABS kicking in and was finally able to go around the object which turned out to be a large cardboard box. At this point is where I encounter my problem, I give the car gas to proceed down the road, the car just revs as if it was in neutral, I look down at my shifter and it is in D. I shift down to lower gears and nothing. Now I'm nervous because I see cars coming to my rear and there is no emergency lane on this road. After 30 seconds of no connection between engine and trans, the trans finally engages and I am able to proceed.
The other time I encountered this disconnection between engine and trans was when I was coming out of a sharp turn and I was doing 35MPH. I gave the car gas to speed up to the oncoming traffic and nothing for 10 seconds, then the engine and trans engage.
During both instances, the "! Light" DID NOT flash.
I spoke to my dealer about this problem and was told that this is a built in safety feature and the CLK is supposed to do this, I don't see anything safe about a disconnection between engine and trans. I do not believe this to be true so I contacted MB USA and reported this issue to their technical coordinator, I am supposed to hear back with in the next 5 business days.