Jump to content

7G-Tronic problem in my CLS


Mmatrix
 Share

Recommended Posts

Neutral Newbie

When changing from 2nd to 1st, there will always be a jerk. In auto mode, there will still be a slight jerk when changing from 2nd to 1st. And I notice that from 2nd to 3rd, the car will pull away slightly quicker just when the gear has been engaged. I've sent the car to C&C for servicing, but to no avail... Any 7G-Tronic users out there facing this problem?

↡ Advertisement
Link to post
Share on other sites

Mercedes auto-transmission isn't jerk free, so it could have some jerks whilst changing gears. However, if its really quite bad, then you should go back to C&C to demonstrate the problem for them. Most they could do is probably to change the transmission fluid or re-program the ecu

Edited by Sturtles
Link to post
Share on other sites

It has to do with the programming software.

 

Previously my dads Citroen C5 had similar problems but after uploading an updated software gear change is brisky and smoother. But still got the down shift problem which they cannot resolve. There's always the thumping feeling from 3rd gear to 2nd.

 

I think the software incorporates the throttle and gear change hand in hand.

 

I wonder why conti have these problems. Probably multi-speed gearbox is still in the tuning stage. The Japanese dun have these problems. @ least for Honda's 5 speed auto it's smooth.

 

The previous models of mercs with 4-speed gearbox have no problems. I think it's still in the stage of perfecting the software.

Link to post
Share on other sites

Neutral Newbie

Went for repairs thrice already and problem is not fixed. So, all Mercedes are like this? $300k for a car with transmission problem.. [:/] However, changing from 2nd, 3rd, 4th all the way to 7th and vice-versa are jerk-free. Its only 2nd to 1st...

 

Its not hard acceleration or pronounced engine brake. It only happened when braking and when the gear shift from 2nd to 1st. It will lag awhile then the huge jerk comes after it.

 

It feels like the clutch is thrown thoughtlessly (manual description).

 

I do hope some other 7g-tronic users may speak up...

Edited by Mmatrix
Link to post
Share on other sites

Sounds like the transmission software isn't well-written.

 

My car (BMW) had the same problem when slowing down to a stop and when it's shifts from 3rd to 2nd (all BMW's start on 2nd gear unless in Sports mode), there will be a jerk.

 

Did some research and found out it was an issue. Called PML and booked my car in for a transmission software reflash. 5 mins with a computer and problem disappeared...

Link to post
Share on other sites

Neutral Newbie
When changing from 2nd to 1st, there will always be a jerk. In auto mode, there will still be a slight jerk when changing from 2nd to 1st. And I notice that from 2nd to 3rd, the car will pull away slightly quicker just when the gear has been engaged. I've sent the car to C&C for servicing, but to no avail... Any 7G-Tronic users out there facing this problem?

its seems that this is quite a common problem for early batches of CLS. do a search in bmwsg

Link to post
Share on other sites

Turbocharged
True, Merc gears do tend to jerk, especially on hard acceleration. It's part of the design.

 

Not trying to start a war here and not blasting the Merc brand but if its part of the design... the designer or the design is really stupid. People want seamless shifting especially for slush boxes and not jerky shifting. Just my opinion

Link to post
Share on other sites

Auto car where got engine brake as compare to manual car?You got drive both auto and manual car before or not?Auto car should stop without jerk.Think the programming got problem.It kicks down the gear too early thus causing the jerk.

Link to post
Share on other sites

Did they flash the new firmware? May not have done so if they think it's not applicable or regular servicing.

 

It's like motherboard BIOS - many people don't flash to update.

Link to post
Share on other sites

Neutral Newbie

My old Ford Mondeo used to have jerky downshifts fron 2nd to 1st...and that happened periodically with no pattern of use - strange to see it still exists in the most technologically advanced gearboxes today.

 

hope you get it resolved soon. Cheers.

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...