Eich

My 04 CLK500 has started to shift really hard when I go from Reverse to Drive unless I completely stop the car and wait a few seconds. It's so harsh, the entire car bucks and jerks the passengers around.

Also, at times, when I shift from Reverse or Neutral to Drive quickly, the transmission slips for a bit, then grabs all of the sudden and the car bucks terribly.

Anyone experience this and know what the fix was at the dealer?

chixdiggit

Are you experiencing a jerk when in drive from first gear that feels like the gear just slipped and caught? Is your CLK a 2003 model with the 5 speed tranny?

Eich

Yes but it's just when I go from Reverse or neutral to drive - like after I've backed out of the driveway. It doesn't do it all the time but when it does, it's very abrupt and harsh. It never does this when I'm sitting at a stop sign or light and then just accelerate off from 1st gear.

2004 CLK 500 w/5-speed auto.

chixdiggit

There are a number of threads where other members have had similar problems with their 2003/2004 cars. I had this problem as well but it mainly affected my acceleration in first gear where it feels like the gears slipped and caught all of a sudden. I'm not sure if you're having the same problem, but it sounds similar. Here's the jist of my understanding:

The radiator cools the transmission in our vehicles. MB was using BEHR radiators which had a defect. I was told that only some of the radiators had this problem and not enough for a recall. Anyways, the hoses would leak and the coolant would contaminate the transmission fluid. I believe this is referred to as "glycol contamination"... I'm not 100%. The contamination would corrode the gears which the outer layer peels and there will be debris in the tranny which further damages the gears.

Many of the dealerships will misdiagnose this problem as a failure in the torque converter and simply replace it. However, the problem will persist and they will be puzzled. I don't believe any code will show up when they run Star Diagnostics which would add to the confusion.

In the end I ended up having my torque converter, radiator, hoses and the entire transmission replaced. The car runs fine and smoothly and fine now. I believe MB also switched to a different radiator to avoid further problems.

Here's the link to one of the threads. There are other ones with additional information floating around the forum.

https://mbworld.org/forums/showthrea...+contamination

Hope this helps and you find the problem.

Let us know how it goes....


Chix

Eich

Hmmm... .thanks for the info Chix.

I'm not sure if what was reported in that thread is what's happening to me but I agree, the symptoms sound like they could be related.

And for sure, there was a time this winter where I had to rock my car back and forth because it was stuck in my driveway due to ice. So, I was shifting back and forth between reverse and drive - not roughly - but enough to rock the car and get it un-stuck. During the rocking, there were several times where I had the car in drive, hit the gas, the rpms went up like the transmission was slipping and then all of the sudden, it grabbed and the car jerked violently.

But recently, I haven't noticed any slipping - but what actually seems to be the opposite. When I back out of my driveway and shift from Reverse to Drive, the car lurches forward harshly like the transmission did slip internally for a split second and then grabbed hard.

I guess I had better take it in soon as my warranty expires this year.

chixdiggit

The symptoms became very noticeable because I too rocked the car back and forth to get it out of a patch of snow. The slipping was every so often and I disregarded it as my driving. After that moment, the slipping became regular.

alboogiee

This has happened to me twice, once on a 07 c230 loaner and a bunch of times on my 05 c230. I have never brought it up to the service dept b/c I cannot succesfully replicate the jerks, so I fully stop my car when backing out of the driveway before putting it in drive. I do have the clunks/grinding/hesitation described by you CLK guys too. I'm pretty tempted now to bring it in.

2-ToneCLK500

I had the same problem on my CLK500. I took it to the dealer and they changed a 12-pin connector. That alleviated the bucking when I would accelerate. But, I always wondered why the car would jerk when I shifted from reverse to neutral, as well as stepping on the gas from a full stop. For example, trying to merge onto the freeway from a complete stop. Then I realized all I had to do was turn off the ESP button when I wanted to punch the gas.
I'm not sure if that's the answer to your problem, but you may want to ask the dealer about the 12-pin connector. Hope this helps.