W203 auto downchange

Discussion in 'Engine' started by krisby, Mar 28, 2014.

  1. krisby

    krisby Hardcore MB Enthusiast

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    An annoying feature of the W203 auto box is that it changes into first before I have stopped, or in very slow traffic. Having had an E39 I loved the smoothness of the gearbox and the fact it would only drop as low as 2nd, making for a much smoother drive in bumper to bumper traffic or stopping at traffic lights.

    Does anyone know if there is a software update for this?
     
  2. nigel cross

    nigel cross Hardcore MB Enthusiast

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    Doesn't sound right to me. How many miles have you done and have you ever had the auto fluid changed?
     
  3. OP
    OP
    krisby

    krisby Hardcore MB Enthusiast

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    its on 92k miles, I've only had it 3 weeks and as I only have a stamped service book, not receipts, I don't know if it has been done.

    I did mention it to my mechanic and he reckoned unless it is causing issues, don't do it, problem is I don't know if this is an issue or just the way it is. If you say its not, then perhaps I should get it done then.
     
  4. brucemillar

    brucemillar MB Club Veteran

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    I have a W203 C240 Petrol, Estate which is a 2004 car.

    The gear box in that is very smooth. What setting do you have the switch in? S or W ?

    The gearbox is adaptive so does learn your diving style. You could get the adaptions re-set on STAR. Warning DO NOT TRY THE HOLD DOWN PEDAL METHOD of re-set. I did and then had al manner of problems with the box. get it done properly on STAR.

    Last but not least. Check the ATF is Red and not burnt. It may be worth getting it replaced. You can get a dipstick on ebay or get an Indie to dip it.
     
  5. OP
    OP
    krisby

    krisby Hardcore MB Enthusiast

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    The switch is in S. Don't get me wrong, it is very smooth otherwise, and smooth on normal downchanges, it is just when going very slow in traffic, perhaps <5mph it changes into 1st, which is not something I would expect on an auto.
     
  6. whitenemesis

    whitenemesis MB Club Veteran

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    You want a smoother ride in bumper to bumper traffic, stick the 'box in W mode. It will use 2nd as the lowest setting, unless you hoof it at take-off ;)
     
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  7. BTB 500

    BTB 500 MB Club Veteran

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    Is this a 5-speed or 7-speed? Doesn't sound normal to me.
     
  8. Rory

    Rory MB Club Veteran

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    I don't know where the change points are but in crawling traffic at <5MPH I would have thought it'd stay in first anyway.

    I can only guess that if it's shifting to 2nd and then back to first then perhaps it's more noticeable in a V6 petrol than it would be in the more usual 4 or 5 cyl diesel?

    As others have said, a "work-around" would be to pop it into W mode - some people drive all the time like that, MB called it C for Comfort in later models. I find in mine it makes it a bit slow off the mark but if you press the gas pedal firmly it'll still drop to first anyway, although it does it with a bit of a jolt.
     
  9. Rory

    Rory MB Club Veteran

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    5 speed.
     
  10. IanMSpencer

    IanMSpencer Active Member

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    I'm sure my 1999 W202 C240 did that - 5 speed auto, and that engine was a run out model engine, probably there to be checked out ready for the 203 so I think the drive train is likely similar.

    Not got it to play with now but I'm sure crawling up to roundabouts it would tend to switch. I was conscious of it because other cars had a tendency to coast and the Merc seemed to hold on to the drive more noticeably. The gearing was more direct than most autos of the era.

    The box dropped its oil round Shrewsbury bypass due to a burst pipe on the cooling radiator, and it needed nursing back into health by the use of some treatment or other. Sully me then drive another 50 miles avoiding a box of neutrals by gentle acceleration. At 150k it was starting to be a little rougher, banging changes on heavy acceleration followed by rapid lift off and also reversing a lot seemed to upset it and would result in a bang shortly after going forward. As it had done about 40k since the oil drop I'm not going to complain.
     
  11. BTB 500

    BTB 500 MB Club Veteran

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    I've got the 5-speed box in the SL (petrol V8) and the Vito (diesel V6) and both are very smooth in slow traffic.
     
  12. grumpyoldgit

    grumpyoldgit Hardcore MB Enthusiast

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    Try it in the other setting. It's C and S (comfort and standard) on my C270, not S and W. Comfort is supposed to start in 2nd gear, unless you boot it, in which case it will automatically select 1st. Pulling away gently it uses 2nd, so it may alter which gear is selected when slowing down as well.

    Haven't noticed anything in mine and can't really say at what speed each downshift gear is selected. I keep mine in S usually.
     
    Last edited: Mar 28, 2014
  13. DSM10000

    DSM10000 Hardcore MB Enthusiast

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    I was stuck in slow moving traffic going into Salisbury this morning, the gearbox (C320 5 speed) changed to first gear at around 4mph.
     

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