E280cdi Jerky Gearchange

[georgen]

Hi all,

I'm pretty new around here, and have just purchased my first MB after 25 years of BMW ownership. It's a 2006 facelift E280cdi in a stunning red ( I've yet to find out the paint name ). Generally, I'm pretty with the purchase, but I have a niggle that's playing havoc with my brain. My autobox is jerky..

Drive the car home over 100 miles, and the first 80 were fine. Coming off a roundabout, I noticed that the gearchange, maybe 3rd -4th, caused the car to lurch. I've found the following.

From standstill with reasonable pace: Jerks 2nd to 3rd. Other gears fine. Seems to be if I pull off slowly though, the jerk waits until it's up about the top gears.

Comfort: under acceleration seems fine. No jerking.

Jerks are more severe in sport mode.

I've just done a gearbox adaption reset, which improved the comfort change ratios no end. But still my problem persists. Any ideas guys ? The web is full of horror stories and I'm not sure what to believe !

Thanks,

George

 

[steveq]

I suggest that the first thing you do is get the ATF & filter changed.
The change should include the Torque Converter drain.
You should go to a Merc specialist to get it done or DIY it if you are up for it. It needs the correct spec ATF, filter, sump gasket and probably a few sump bolts.
It might not resolve the issue but at least it will eliminate an obvious possible cause.

Good luck with your purchase.

 

[georgen]

Many thanks for the response.

Have been to see my trusted mechanic today, and we've found the issue only exists between 3rd - 4th upshifts. The conductor plate is a suspect, but I'm very keen to change the 7g oil and filter as you've suggested. That'll happen tomorrow. Here's hoping..

 

[steveq]

Hi,
I didn't realise that you have the 7G gearbox. That means that you must replace all the sump bolts as they are single use stretch bolts.
There was a change to sump pan shape -- the replacement had a revised shape with more of a slope at the front. I think it was to resolve an oil surge issue. Worth checking if you have the newer shape sump pan.

If you have identified a clear problem with one specific change I doubt if changing the ATF will resolve it. I suppose it depends on how severe the jerk is during the changes. The fresh ATF should make it smoother overall.

Is there any history of an ATF change being done previously?

 

[georgen]

He's going to have a rake around in the box tomorrow to see if anything is obvious. Maybe even remove the valve block to give it a clean out. I've read some good reports online with folks having had this done.

The history was patchy at best with this car, so I'm calling the gearbox oil as the original fill. I'm guessing that it can't hurt to change it, and also means that if I do need to change the TCM, I'll not need to drain the Torque Converter again. That's how I'm justifying it in my head anyway.

TBH, any W211 that I would have bought would have had the gear oil changed anyway. I had just hoped that problems would not have appeared in my first hour of ownership !

Thanks again.

 

[AndrewOl]

An oil service is a good idea and if the tcu is playing up the gearbox will start going into limp mode. This usually only happens sporadically and is reset by cycling the ignition. Fair warning to get the tcu replaced. I think mb do recon units that a good indie will fit. Not really a home job.

 

[georgen]

No difference after gearoil change. And we've found sevel other issues including major engine oil leaks.

To that end, I've called no joy with the car. It's in the process of being returned to the dealer as I write.

Too many issues for a car that was sold as roadworthy...