C250 CGI gearbox problems

[sld]

I have a 2010 C250 CGI with the 5 speed auto box. Bought it from new and the mileage is just under 10k after 20 months. Great car but it's developed a nasty problem: if you're travelling at a steady speed and suddenly want to accelerate quickly to overtake, the box hesitates for a second or two (with a sort of dribbling vibration through the pedal), doesn't go any faster, and then the car lurches into life. Somewhat dangerous if you need to pull out and overtake swiftly, particularly if there's someone else behind you with the same idea). It has also happened once pulling off from stationary at a junction (equally scary).

I took the car to my dealer and they did a software update a month ago, which they said would cure the problem, but it happened again today. (Incidentally, after the update the car became very difficult to brake smoothly at low speed in town with inconsistent brake feel through the pedal, but that seems to have cured itself now).

Any views/similar experiences would be appreciated. I've heard of problems with the 7-G tronic auto but not with the 5 speeder that mine has (which they've ditched now on the latest facelifted C Class).

 

[markjay]

Firstly, be aware of this issue:

http://www.mbclub.co.uk/forums/engine/98252-sluggish-gearbox-when-pulling-away.html

This is common on many of the 5-speed auto transmissions. I have this on mine.

But if this is a situation that got worse over time, and/or there's a vibration as you describe, then this isn't right.

Do you know if they found any error codes logged while the car was connected to STAR? Has the MB dealer checked the transmission fluid level? And what's the mileage? If over 35k, I would consider a fluid and filter change.

 

[sld]

Many thanks for your reply: I've just read the posts on the link you gave, which was very helpful, if slightly worrying reading! Can't say it endears me to replacing it with another Mercedes if that's par for the course, mind.

The dealer didn't give any details when they said they'd fixed it (except they had to upload the update twice as after the first time, they couldn't get the car to start lol). The car was serviced 6 months ago, so I would have thought a fluid and filter change wouldn't be necessary (at least not yet, particularly as the car's only 20 months old).

 

[tjs_riley]

I've been having this problem since I got the car new in Feb 2011. Now that it is out of warranty, the local Kleeman dealer told me that his K-Box for the 1.8 C250 CGI BlueEfficiency engine would solve it by running a different map.
I ended up installing a similar system , a Carlsson C-Tronic piggyback box because the Carlsson kit came with a larger intercooler whereas the Kleeman makes do with stock.

More power definitely BUT STILL have the same problem with low end shake. You described it exactly : "travelling at a steady speed and suddenly want to accelerate quickly to overtake, the box hesitates for a second or two (with a sort of dribbling vibration through the pedal), doesn't go any faster, and then the car lurches into life"
Same solution by Dealer, transmission software reflash (twice!) , Still the same problem.
I might note that mine has the 5 speed gearbox and not the 7-G-Tronic if that makes a difference.
Did you find a solution in the end ?