CLS Gearbox

[gjlelec]

Hi, i'm after some advice. I have a 2006 5.0 Ltr CLS. (69,000 miles) The problem i'm encountering is with the auto gearbox. All shifts are smooth and fine except when you are coasting up to a junction or a roundabout etc . Just before coming to a halt, the gearbox seems to make an early grab at first gear (thats the only way i can describe it) causing an unpleasant jolt. The problem is worse when the gearbox is cold but still unpleasant when warm. I've tried the "reset the gearbox" methods shown on Youtube. I'm not sure if these (various) methods actually do anything as its made no difference at all. My plan is to get my indie to change the gearbox oil and filter, reset the gearbox with Star and then see if it improves. I know virtually nothing about how an auto box works but is there anything else worth changing , (solenoid pack ? tubes ? foo-foo- valves ?) while the pan is off to potentially improve this ?
Thanks for any suggestions

 

[Blobcat]

When was the ATF last changed?

 

[LostKiwi]

When your indy changes the oil have him read the error codes if there are any.
Adaptations could be reset too but in general they seem to self adapt pretty well.

 

[Jim2]

When was the ATF last changed?

Just a general observation Blobcat..I know full well the amount of problems that can be caused by mechanical / electrical part's failure, but pound for pound, for something relatively simple, transmission fluid punches way above it's weight in terms of issues.

 

[Uncle Benz]

Early 7G tronic, like you have, are renowned for this fault. Cole at MBS used to be very good at manually adjusting the shift parameters to minimise this annoying thump. I dare say he still has the knack. Worth a chat with him at the vary least.

 

[gjlelec]

Service history shows gearbox oil and filter change at 37,000 (approx 32,000 miles ago) - thanks

 

[Wighty]

Service history shows gearbox oil and filter change at 37,000 (approx 32,000 miles ago) - thanks

Steve at Avantgarde Mercedes (Indy) near Bristol May be worth a trip .

 

[GordonTarling]

The gearbox should only change down to first when it's in sport mode - is this what's happening? If it's doing it in 'C' mode, then something is badly wrong.

 

[V6Matty]

The gearbox should only change down to first when it's in sport mode - is this what's happening? If it's doing it in 'C' mode, then something is badly wrong.

Not true on the early 7g boxes, it’s a known issue and can only be fixed by manipulating the 2-1 shift parameters as Uncle Benz suggested.

 

[sonic]

The gearbox should only change down to first when it's in sport mode - is this what's happening? If it's doing it in 'C' mode, then something is badly wrong.

My 2011 212 E350Cdi with the 7G box certainly goes into 1st gear when I stop. It also does it with a little clunk when cold, something I have just lived with for 8 years.

 

[gjlelec]

What does "manipulating the 2-1 shift parameters as Uncle Benz suggested" entail ? I've had very good service from Sinclair Mercedes Bridgend in the past when i owned a 5.5 SL. I was thinking of taking it there if all else fails. Am i right in assuming this is a fault ? Or a characteristic of the early 7G boxes ? I cant believe it would have behaved like this from new

 

[Uncle Benz]

A little info for you

http://www.askatech.com/AskATechLive/forums/ResourceHandler.ashx?a=4552

 

[Gazwould]

Got one of those for a 7G+ ?

 

[gjlelec]

One of my pet hates on forums such as this, is when someone posts a problem and you never get to hear if it was resolved by what was suggested, so heres an update. Had the atf drained , filter removed and box reset on "Star" to manufacturers settings. (My indy happily admitted to not having a clue what "manipulating the shift parameters" was) Anyway, the new oil/ filter has transformed the car. The thump is still present when cold but far less pronounced. When warm, its completely disappeared. I also noted the old oil was black, (though it didnt smell burnt) and the filter quite dirty.In my mind i was expecting it to be red ? Sooner or later i will have to send it in to the official stealer for something, no doubt. Then i'll probably ask if they can eliminate the thump when cold too. Thanks for the advice all

 

[Wighty]

One of my pet hates on forums such as this, is when someone posts a problem and you never get to hear if it was resolved by what was suggested, so heres an update. Had the atf drained , filter removed and box reset on "Star" to manufacturers settings. (My indy happily admitted to not having a clue what "manipulating the shift parameters" was) Anyway, the new oil/ filter has transformed the car. The thump is still present when cold but far less pronounced. When warm, its completely disappeared. I also noted the old oil was black, (though it didnt smell burnt) and the filter quite dirty.In my mind i was expecting it to be red ? Sooner or later i will have to send it in to the official stealer for something, no doubt. Then i'll probably ask if they can eliminate the thump when cold too. Thanks for the advice all

Good update buddy , everyone hates unresolved threads/problems , apart from the punter who gets the advice and disappears into the ether . At least until their next problem .
With regard to the gearbox thump , maybe some of the engine “mappers” are able to alter this ? Maybe someone like Alex at AMF Automotive would know ....he does some engine/gearbox tweaking

 

[gjlelec]

Is AMF Automotive near me ? As my avatar shows , i'm in Swansea - thanks

 

[V6Matty]

You’ve got Avantguard automotive near Cleavdon almost on your doorstep there, well worth a trip, https://www.avantgarde-automotive.co.uk/

 

[bembo449]

great update , if you have a recommended indy close enough I would not take it anywhere near a stealers pal

 

[Jim2]

Good update buddy , everyone hates unresolved threads/problems , apart from the punter who gets the advice and disappears into the ether . At least until their next problem .
With regard to the gearbox thump , maybe some of the engine “mappers” are able to alter this ? Maybe someone like Alex at AMF Automotive would know ....he does some engine/gearbox tweaking

Dead right Wighty, the members of this forum are unstinting in their effort's to help anyone who request's it. And it would be just good manner's to acknowledge it by following through with the result's ( or lack of ) But human nature being what it is...just don't get your hope's up, and that way you will not be dissapointed !!!

 

[John Laidlaw]

Indeed thanks for the update it helps others going forward