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Automatic Gear Change

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by Fotherm, Jan 11, 2017.

  1. Fotherm

    Fotherm New Member

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    Joined:
    Sep 3, 2014
    Location:
    warwick
    Your Mercedes:
    C Class / 2006/ 3000
    Grateful if anyone could advise on the recent problem my C320 has developed - occassionally the car will not go into the next gear at around 50 mph. If I switch off the engine the problem is resolved. Any advice welcomed
     
  2. Flyinspanner

    Flyinspanner Senior Member

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    Joined:
    Aug 8, 2010
    Location:
    Ruislip
    Your Mercedes:
    CL500 -W215, A140-W168
    How many miles has it done?

    Is the transmission fluid at correct level?
    How does fluid look? (Hopefully cherry red, sweet smelling)

    If brownish or smells 'burnt' then you may well need a fluid change (has it ever been done in the past?)

    If looks n smells ok, then get a STAR diagnosis.

    If it feels sluggish and won't change up or down, (have you tried 'manually'- tapping selector sideways) then it may be the speed sensor on the gearbox electric 'plate' - it would be around £400 at an Indy inc trans fluid & filter.
     
    Last edited: Jan 11, 2017
  3. umblecumbuz

    umblecumbuz Senior Member

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    Joined:
    Sep 20, 2010
    Location:
    Wales and Gozo
    Your Mercedes:
    S204 and CLC 204 cdi, other non-Merc machines
    Check fluid level before doing anything elee.
    If it hasn't been regularly serviced, this is the obvious first step.

    Umble
     
  4. Steve@Avantgarde

    Steve@Avantgarde Forum Supporter Authorised Forum Supporter

    Messages:
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    Joined:
    Dec 8, 2009
    Location:
    Bristol/Somerset
    Your Mercedes:
    Mercedes-Benz C32AMG and SLR McLaren Coupe 2005.
    Valve in the valve body is sticking or the speed sensor on the TCU is filthy so it cannot read a permissible speed ratio.

    You can try removing it, cleaning it and flushing the ATF, if it still happens after that then a new TCU will be required.
     

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