7G Tronic - wasn't able to switch from N to D?

Discussion in 'Engine' started by Mertz33, Jul 31, 2019.

  1. Mertz33

    Mertz33 New Member

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    Hi all,

    2007 CLK280 owner so the M272 with the 7G tronic transmission - was at a traffic light in Neutral and changed to Drive but no reaction, engine was revving fine yet car not moving forward.

    Went back and forth between Neutral and Drive few times without success then I pressed the Sport button (was in Comfort before) and clank, the car was moving again..

    The whole things lasted enough for the light to go back red - I wonder why did this happen?

    Cheers
     
  2. dynamicq

    dynamicq Active Member

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    Could be the fact that in sport it starts in first gear...could the frictions be worn out... You can see the gearbox wear indication (adaptation values) in Xentry. Your local indie should have it. Does the gearbox kicks normally or smoothly changes the gears, what's the milage. Does it have gearbox service history.

    Sent from my Mi A2 using Tapatalk
     
  3. zipdip

    zipdip Hardcore MB Enthusiast

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    If it does it again,put the car into park and switch it off then start it again and see if the car goes,as per the previous post,get it to a indy and get the box tested,you may beed the speed plate repaired,it just might need a service.
     
  4. whitenemesis

    whitenemesis MB Club Veteran

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    Why were you in neutral?
    Handbook recommends staying in drive unless stopped for a prolonged period.
    Probably of no relevance to your issue but just curious.
     
    ivan1983, DSM10000 and NDFR like this.
  5. slade1

    slade1 Hardcore MB Enthusiast

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    Had similar problem with my 05 ClK 7 speed, new electroplate.
     
  6. renault12ts

    renault12ts MB Club Veteran

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    I wonder if you would have to do this during a driving test?
     
  7. BlackC55

    BlackC55 Authorised Forum Sponsor Authorised Forum Sponsor

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    Low fluid level can cause this. Id get it plugged in firstly.
     
  8. OP
    OP
    Mertz33

    Mertz33 New Member

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    Thanks all for your replies, I've been away for a while.

    The car has done just under 60k, gear change is smooth has a (full?) MB service history although I haven't seen any mentions of the gearbox.. This was the only time it happened and seemed more electronic than mechanical (other people also told me to switch off & on again).
    Will take it to a garage to have it checked..
     
  9. OP
    OP
    Mertz33

    Mertz33 New Member

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    Which Handbook? :)

    If it's a short stop, something like 30 seconds yes, I wouldn't bother but otherwise I don't see the point having that extra load on the torque converter when I know I'm not moving forward..
    I was something like the 5th car at the light and it was a longer red that I knew of so of course I would wait in neutral-


    Cheers
     
  10. whitenemesis

    whitenemesis MB Club Veteran

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    The owner's handbook.
    Here's a (lengthy) explanation as to why shifting to N at lights is not recommended.
    Use of Neutral Gear in Automatic Transmission
     
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  11. Jockcl500

    Jockcl500 Hardcore MB Enthusiast

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    That is a good description of what is going on, I never use neutral(unless I am working on the rear brakes and then the engine is turned off), only park to reverse to drive and to park again.
     
  12. OP
    OP
    Mertz33

    Mertz33 New Member

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    You were right, I looked this up in the handbook and it does say Neutral is not necessary for short stops.
    However I do not agree in full whith what's presented in Mark's answer via the link.. I mean, the arguments are a bit thin: 'I have been told by an automatic transmission engineer'... and it's dangerous to be in Neutral.

    Genuine question though, what causes more wear/is less economic? Additional friction of the clutch plates in N (for a clutch, this is by design.. these plates are optimised for friction) or the torque converter constantly pushing when engaged in D while holding the brakes?


    All that aside, I came back here with an update as I had the gb tested and I think I got all errors relevant to a faulty conductor plate:
    722.9 diagnostic.png

    Disappointed as this seems a common fault and the guy quoted me £1000 for repairing the existing electroplate..

    Is anyone able to recommend a shop somewhere around South London-Croydon-Sutton area? what's an average cost for this repair?

    Second, I looked up some videos/guides and it's frustrating as I'd be able to remove this myself and get it repaired (~£250 to repair my plate), I have the right tools but I don't have a way to get unde the car (lift? ramp?).. and after removing the conductor plate in order to send it for repair, I wouldn't be able to drive the car until I get it back... any suggestions?


    Thanks all in advance!
     
  13. ToeKnee

    ToeKnee Hardcore MB Enthusiast

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    Four axle stands and a hire car/taxi? Should still be cheaper than £1000!
     
  14. OP
    OP
    Mertz33

    Mertz33 New Member

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    I thought so! but not sure the axle stands are tall enough for what I need plus I'm a bit converned about (my) safety :D
     
    ToeKnee likes this.
  15. slade1

    slade1 Hardcore MB Enthusiast

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    If it is the electroplate, around £500 at indie. It failed at 55K miles.
    It does look like your problem is the electroplate.
     
  16. DSM10000

    DSM10000 MB Club Veteran

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  17. OP
    OP
    Mertz33

    Mertz33 New Member

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    A bit far from where I live but I'll give them a ring, thanks
     

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