Transmission issue?
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Joined: Dec 2010
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From: Wichita, KS
2009 C300 Luxury P1 w/Multimedia, Arctic White
Transmission issue?
I know there have been dozens of posts about strange transmission shifting issues, but I'm going to post one more...
Basically, when the engine is cold, shifting from Reverse to Drive is pretty hard. When it's warm, no problems. At first, there was the delay issue going from Park to Reverse. I took the car to the dealership and they applied the transmission software update and that took care of the delay problem. But the hard shift from R to D persists. While in drive, upshifting and downshifting is smooth. I took the car back to the dealership today and they said it was a normal characteristic of the car. I just can't accept that explanation. I used a 2011 loaner and the transmission was perfectly smooth all around. Do any of you guys with the 7 speed notice hard shifting when changing directional gears? It drives me nuts, but I'm not real sure what to do at this point. 
Basically, when the engine is cold, shifting from Reverse to Drive is pretty hard. When it's warm, no problems. At first, there was the delay issue going from Park to Reverse. I took the car to the dealership and they applied the transmission software update and that took care of the delay problem. But the hard shift from R to D persists. While in drive, upshifting and downshifting is smooth. I took the car back to the dealership today and they said it was a normal characteristic of the car. I just can't accept that explanation. I used a 2011 loaner and the transmission was perfectly smooth all around. Do any of you guys with the 7 speed notice hard shifting when changing directional gears? It drives me nuts, but I'm not real sure what to do at this point.
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From: Acapulco Mexico
2010 C300 Sport
Check this thread - apparently this problem got fixed.
https://mbworld.org/forums/c-class-w...rse-delay.html
https://mbworld.org/forums/c-class-w...rse-delay.html
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Joined: Sep 2009
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From: Dix Hills, New York
2012 C250 Coupe
I don't think he is talking about a transmission delay when switching gears, but rather, rough shifting? Am I right OP?
Anyway, my car shifts rough when its really cold out (especially during the lower gears and from reverse to drive but goes away when the car has been warmed up.
Also, sometimes I have a rough shift from drive to reverse. But the only times I have experienced that is when I do a quick shift and may have not fully come to a stop.
Anyway, my car shifts rough when its really cold out (especially during the lower gears and from reverse to drive but goes away when the car has been warmed up.
Also, sometimes I have a rough shift from drive to reverse. But the only times I have experienced that is when I do a quick shift and may have not fully come to a stop.
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Joined: Oct 2008
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2010 C300
OMG! i'm having the same problem! my car was in the show for the whole week last week and they say they can't "duplicate" the problem. So i went in one afternoon after the car has been sitting for a while, it was even really bad from P to R. actually, it was so bad that the whole car shook. i brought a service advisor up with me to try it, and he admitted that he did feel it, and the dealer agreed to hold my car one more night to have the foreman look at it. however, the next day, they say they can't duplicate the problem AGAIN! they gave me the car back and said they will have a Technician Specialist from MB to come down and look at it. It's just strange that it happens to me EVERY cold start, but the technicians at the dealers do not feel anything...
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
You need to be clear on what the problem is. If you have the latest TCU flash the transmission should shift smoothly.
However - these cars go into high idle when cold to warm up the Cats quickly for emissions reasons - they also hold gears for a little longer than normal until warm due to the same thing.
If you get a bit of a jerk when selecting drive or reverse when cold this is usually due to the idle speed being high & nothing else. i.e no fault. You also need to be a little patient with Benz trannys & not accelerate until drive or reverse is fully engaged & the electrohydraulic unit is up to full pressure or you can induce a severe jerk.
If the up changes or down changes of the transmission are harsh - then something is wrong.
Make sure the transmission is serviced with oil & filter chance EVERY 39K miles or 60K km's.
However - these cars go into high idle when cold to warm up the Cats quickly for emissions reasons - they also hold gears for a little longer than normal until warm due to the same thing.
If you get a bit of a jerk when selecting drive or reverse when cold this is usually due to the idle speed being high & nothing else. i.e no fault. You also need to be a little patient with Benz trannys & not accelerate until drive or reverse is fully engaged & the electrohydraulic unit is up to full pressure or you can induce a severe jerk.
If the up changes or down changes of the transmission are harsh - then something is wrong.
Make sure the transmission is serviced with oil & filter chance EVERY 39K miles or 60K km's.
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From: Wichita, KS
2009 C300 Luxury P1 w/Multimedia, Arctic White
Thanks guys for posting!
@ jctevere, yeah the car "jerks" when changing from R to D only when the engine is cold. I usually let the run for 30 seconds or so to let the engine idle down below 1K RPM's.
@ victort, I feel your pain. Out of curiosity, what year is your C? Mine, like yours, does it EVERY time when cold. Please please please, let me know if MB finds a fix for you!
@ Glyn, yes I have the latest TCU flash but that didn't correct the problem. I never attempt to accellerate until the gear is fully engaged. I've only got 16K so a transmission fluid/filter change isn't yet required.
@ jctevere, yeah the car "jerks" when changing from R to D only when the engine is cold. I usually let the run for 30 seconds or so to let the engine idle down below 1K RPM's.
@ victort, I feel your pain. Out of curiosity, what year is your C? Mine, like yours, does it EVERY time when cold. Please please please, let me know if MB finds a fix for you!
@ Glyn, yes I have the latest TCU flash but that didn't correct the problem. I never attempt to accellerate until the gear is fully engaged. I've only got 16K so a transmission fluid/filter change isn't yet required.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Thanks guys for posting!
@ jctevere, yeah the car "jerks" when changing from R to D only when the engine is cold. I usually let the run for 30 seconds or so to let the engine idle down below 1K RPM's.
@ victort, I feel your pain. Out of curiosity, what year is your C? Mine, like yours, does it EVERY time when cold. Please please please, let me know if MB finds a fix for you!
@ Glyn, yes I have the latest TCU flash but that didn't correct the problem. I never attempt to accellerate until the gear is fully engaged. I've only got 16K so a transmission fluid/filter change isn't yet required.
@ jctevere, yeah the car "jerks" when changing from R to D only when the engine is cold. I usually let the run for 30 seconds or so to let the engine idle down below 1K RPM's.
@ victort, I feel your pain. Out of curiosity, what year is your C? Mine, like yours, does it EVERY time when cold. Please please please, let me know if MB finds a fix for you!
@ Glyn, yes I have the latest TCU flash but that didn't correct the problem. I never attempt to accellerate until the gear is fully engaged. I've only got 16K so a transmission fluid/filter change isn't yet required.
Anyway - whatever the problem - the fix is to repace the entire valve body as a unit. Benz does not allow repair of the valve body & it comes completely set up from Germany.
They have paid for a number of valve body replacements on C350's on the W203 forum. Karo's transmission being the most recent IIRC.
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From: Acapulco Mexico
2010 C300 Sport
If a valve body unit replacement is required, as Mr Ruck suggests, it is a very complex process as the valve action has to be "married" to each transmission. I would only go to a MB service that had successfully done many of these replacements on the 7G tranmission. Other threads describe the process of matching the valve unit to each particular transmission.
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2010 C300
ok, so i get a call today from my local mb dealer. they said that they are going to have to check my car again, and either going to update my software again (done prior, but "newer" update) or to replace my control unit in the valve body. can anyone explain what exactly is this process? is it a major repair job? or is it more of taking the old part out and putting the new part in, since it sounds like Glyn Ruck is saying that MB is not allowed to "repair" but more replace with a new unit. any help is appreciated TIA
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From: NJ
Mercedes Benz C300 4matic 1967 Chevelle SS
Here is a Mercedes TSB related to a harsh shift from park to drive, may affect from park to reverse also?
Harsh engagement when changing gear range from P to D
Topic number LI27.50-P-049281Version 1Design group 27.50 Gear assemblyDate 04-06-2010Validity Transmission 722.9
Reason for change
Reason for block
Complaint:
When changing gear range from P to D, harsh engagement may be noticeable.
Cause:
The engagement sequences for N-D and N-R may not be optimized
Remedy:
The engagement sequences for N-D and N-R must be taught in again as follows:
Note:
Always remain in the gear ranges N/R/D for at least 5 sec!
Start the engine from cold,
shift 5 times N-R,
shift 5 times N-D --> warm up transmission to 40°C and while doing so, exceed a speed of 50 km/h at least once.
shift 5 times N-R,
shift 5 times N-D --> warm up transmission to 70°C and while doing so, exceed a speed of 50 km/h at least once.
shift 5 times N-R,
shift 5 times N-D.
Harsh engagement when changing gear range from P to D
Topic number LI27.50-P-049281Version 1Design group 27.50 Gear assemblyDate 04-06-2010Validity Transmission 722.9
Reason for change
Reason for block
Complaint:
When changing gear range from P to D, harsh engagement may be noticeable.
Cause:
The engagement sequences for N-D and N-R may not be optimized
Remedy:
The engagement sequences for N-D and N-R must be taught in again as follows:
Note:
Always remain in the gear ranges N/R/D for at least 5 sec!
Start the engine from cold,
shift 5 times N-R,
shift 5 times N-D --> warm up transmission to 40°C and while doing so, exceed a speed of 50 km/h at least once.
shift 5 times N-R,
shift 5 times N-D --> warm up transmission to 70°C and while doing so, exceed a speed of 50 km/h at least once.
shift 5 times N-R,
shift 5 times N-D.
Junior Member
Joined: Sep 2010
Posts: 67
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From: NJ
Mercedes Benz C300 4matic 1967 Chevelle SS
Here is another of interest:
DELAYED ENGAGEMENT OF REVERSE GEAR
Topic Number LI27.00-P-047119Version 1Design Group 27.00 GeneralDate 06/24/2009Validity Transmission 722.9 with code 809Reason for change Additional procedure for remedy
Reason for block
Complaint:
When reverse is selected, the engagement sequence may be delayed.
A double jolt may occur at an interval of approx. 3 seconds after moving the gearshift lever from P to R.
The complaint occurs with electrohydraulic controller (EHS) 220 270 2406 and 220 270 2306.
These electrohydraulic controllers are installed in transmissions as of model year 2009 (code 809).
Cause:
Parameterization of adaptation values for clutch pack BR (reverse gear)
Remedy:
1. Perform software update in transmission control unit and then perform SCN coding.
It is absolutely essential to make sure that DAS version 01/09 or higher including add-on 1077 is used.
2. Then the reverse gear adaptation data must be reset using DAS (menu guide in attachment).
3. The engagement sequences for N-D and N-R must be taught in again:
NOTE:
Always remain in the gear ranges N/R/D for at least 5 sec!
Start the engine from cold,
shift 5 times N-R,
shift 5 times N-R --> warm up transmission 40°C and while doing so, exceed a speed of 50 km/h at least once.
shift 5 times N-R,
shift 5 times N-D --> warm up transmission to 70°C and while doing so, exceed a speed of 50 km/h at least once.
shift 5 times N-R,
shift 5 times N-D.
DELAYED ENGAGEMENT OF REVERSE GEAR
Topic Number LI27.00-P-047119Version 1Design Group 27.00 GeneralDate 06/24/2009Validity Transmission 722.9 with code 809Reason for change Additional procedure for remedy
Reason for block
Complaint:
When reverse is selected, the engagement sequence may be delayed.
A double jolt may occur at an interval of approx. 3 seconds after moving the gearshift lever from P to R.
The complaint occurs with electrohydraulic controller (EHS) 220 270 2406 and 220 270 2306.
These electrohydraulic controllers are installed in transmissions as of model year 2009 (code 809).
Cause:
Parameterization of adaptation values for clutch pack BR (reverse gear)
Remedy:
1. Perform software update in transmission control unit and then perform SCN coding.
It is absolutely essential to make sure that DAS version 01/09 or higher including add-on 1077 is used.
2. Then the reverse gear adaptation data must be reset using DAS (menu guide in attachment).
3. The engagement sequences for N-D and N-R must be taught in again:
NOTE:
Always remain in the gear ranges N/R/D for at least 5 sec!
Start the engine from cold,
shift 5 times N-R,
shift 5 times N-R --> warm up transmission 40°C and while doing so, exceed a speed of 50 km/h at least once.
shift 5 times N-R,
shift 5 times N-D --> warm up transmission to 70°C and while doing so, exceed a speed of 50 km/h at least once.
shift 5 times N-R,
shift 5 times N-D.
Junior Member
Joined: Sep 2010
Posts: 67
Likes: 0
From: NJ
Mercedes Benz C300 4matic 1967 Chevelle SS
http://www.youtube.com/watch?v=6Svl0...yer_detailpage
Watch this video also, not the same trans, but basically the same sh*t!
Watch this video also, not the same trans, but basically the same sh*t!
Junior Member
Joined: Sep 2010
Posts: 67
Likes: 0
From: NJ
Mercedes Benz C300 4matic 1967 Chevelle SS
THIS is the video you want to see!!!!
http://www.youtube.com/watch?v=gzuXL...yer_detailpage
Mercedes trans control unit replacement!
http://www.youtube.com/watch?v=gzuXL...yer_detailpage
Mercedes trans control unit replacement!
MBWorld Fanatic!
Joined: Oct 2010
Posts: 1,128
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From: Acapulco Mexico
2010 C300 Sport
To get a grip on the complexity of the 722.9 7G transmission, flip through this training manual by MB Hong Kong. Some of the wording reminds us that all who speak English are divided by a common language.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Junior Member
Joined: Sep 2010
Posts: 67
Likes: 0
From: NJ
Mercedes Benz C300 4matic 1967 Chevelle SS
Senior Member
Joined: Oct 2008
Posts: 396
Likes: 2
2010 C300
They had to hold it one more day to test it to make sure everything was installed correctly and fixed the issue. hopefully, i can pick it up after work today. Been driving an impala as a loaner since monday! Hate this car lol
