My 2004 C320, still in warranty, has been developing a problem… I’ve had it a year but only put approx. 1200 miles on the car… A week or so ago I noticed it, my best description, shifting hard… It seemed every time it shifted it jerked very noticeably. I drove it about 10 miles before I heard a muffled grinding sound… It didn’t last but a few seconds… I drove it approx. 35 miles without incident… Parked it for several hours and drove home… No problems… The second time… yesterday… I noticed the very same thing but it only lasted the first 2 or 3 miles… After 12 hours parked… All was fine when I drove home… Now this morning… I’m afraid to drive it… Going down my driveway it was like someone was aggressively hitting the breaks, as I took my foot off the accelerator… Two really good jerks… It sporadically jerked, aggressively, as I drove it about half a mile… The same when I turned on a main road and accelerated… I’ve never let it go below half a tank of gas… I buy Shell gasoline… However, the hours I’ve been keeping I let it get below a quarter of a tank… Any ideas??

 

certain cars mostly C class and CLK have this problem with antifreze entering into the trans oil due to bad radiators. you will probably need torque converter and maybe trans and also a newer control module. this typically on prodution dates on or before 9/03 with a Valeo radiator.

 

I do appreciate the reply...

I'm not certain how to assertain what radiator I have... However, the production date was 3/04

 

if car is under warranty def take it in to the shop. they do have troubles with the torque converter staying in the locked position and does cause transmission shudder when light on the throttle.

 

Well... I took it to the shop on Sept. 11... They concluded I was a quart low on transmission fluid... It is possible... The drive home was without incident... However, my problem has been only when it's cold... I drove it for the first time, since the service, this afternoon... The same thing is happening... The car actually rocked when it shifted at 20 mph... It's the noise, grinding/grating (the closest I can describe it), that is the most worrisome... It’s back to the shop on the 18th... I'll post an update a few days after...

 

right after i repllied to your post I had a CLK with 11/03 production date and i performed a glycol test, and the car needed a radiator, new trans control unit and flush out the trans lines and the car runs fine now. The noise you hear is what the repair bulletin calls a buzzing or droning sound and it does buck and shudder when shifting. the tech working on your car should immediatly know what the trouble is.

 

Your reply is very appreciated... I am most grateful for the expressive wording... Saying the car is bucking and droning is much more precise…

 

They tell me my '04 C320, 03/04 production date, does not fit the Service Bulletin... It does not have the Valeo radiator... I don't think they did a glycol test, at least yesterday, while I was waiting... I read somewhere it's not only the radiator but the type of welds used... No matter... Right now they have it... I can't reproduce the problem except from a cold start... I left it with them yesterday... We'll see what happens next...

 

hey thanks for the update, im curious to know what they find. is your car a 4matic?? some models did have issues with the transfer case fluid and they drain it and put in different gear oil to make the noise go away, this usually only occurs on sharp turns though. i dont really think that that is your problem but Im just throwin it out to you......... as for the problem your having it sounds like torque converter issue, or sometimes the transmission electrical connector leaks, then trans fluid works its way up through the wire harness then the oil goes into the transmission control unit and can cause numerous issues with trans. both are fairly common problems.

 

Mine is not a 4matic... I really appreciate your input... It has been most helpful... The service advisor called late yesterday... The service tech was able to recreate the problem yesterday morning... They are replacing the transmission control unit... I'll have it back today or tomorrow... I'll get more details when I pick it up...