Hello,

I've got a 2003 C230K with 184,000 miles. I've had a recent problem that developed suddenly this summer after the car sat for about 7-8 days. Upon starting the engine and allowing it to idle for approximately 1 min (no longer at high idle speed), I shifted to reverse to back out of the driveway. The transmission didn't jerk or abruptly shift, but it was as if the car didn't want to stop moving as the car jerked suddenly backwards. I hit the brakes to prevent it from moving uncontrollably and the engine started shuttering considerably as if it was under a tremendous load. I continued backing and a similar thing happened when I shifted to drive once I was out on the street. After driving the car a few miles with a few stop/starts (city driving), the engine shuttering and lurching forward subsided considerably. The problem persisted for a few days/weeks, but got continually better everyday until it was nearly not noticeable.

Just a couple days ago, the same thing happened only worse than the very first time. And this time only after sitting overnight. I started the engine and allowed it to idle down a bit (maybe 30-45 secs), shifted into reverse with my foot off the brake as I normally do (I know that's not a good idea), and the car abruptly jerked backward going nearly 5 mph while the engine began shuttering until the car started moving freely. So I hit the brakes to stop the car from moving so quickly having to a apply quite a bit of brake pressure to make it fully stop and the engine began shuttering tremendously again, this time not able to overcome the load at idle. The tachometer dropped to 250 rpm or so, so I quickly shifted to neutral to prevent the engine from stalling. Upon shifting to neutral with the drivetrain under this load, there was a loud clunk that I assume was the driveshaft being relieved of the load.

Once I got the car on the road, the issue slowly improved as I drove. The transmission shifts beautifully as it should. This engine shuttering stops if I so little as take my foot of the brakes and just let it roll at idle speed. Currently the car still has the hard jerk after shifting to gear (especially after sitting for a while), but not nearly as bad as the previously explained condition, that improves considerably after driving the car a few miles. The driveshaft (or at least that's what it sounds like) still makes a faint clunk noise when shifting into/out of gear. It's as if this is a manual transmission and it's constantly dropping the clutch (i.e. not clutching action). It's either engaged or disengaged and no in-between. Therefore, I don't believe it's directly related to the transmission itself. Perhaps the flywheel or torque converter?

Let me know what you think. I appreciate any suggestions/comments in advance! Thanks!