722.6 Autobox advice

CloudSurferUK

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Ok, first question and have seen bits of the answer in other places but hope you don't mind me posting the specific questions I would like answers to.

The car is a 2008 W203 C220 CDI Coupe with 722.6 5-Speed Transmission.

Very occasionally (twice in 10 days & usually after hard acceleration) the gearbox has stopped changing up (limp mode?) - after reading various posts I'm looking at the ATF fluid so.

1. The dipstick cap had a locking tab (black not red) so am I right in assuming its probably never been changed?
2. On dispstick ATF fluid was black but still translucent (isn't ATF fluid red?)
3. Have also invested in the plug with the o-rings that apparently is infamous. do the symptoms fit that?
4. If a change of fluid & the plug doesn't solve it, whats next electroplate? Happy to spend a few quid chasing the problem love the car but there are limits.
 

LostKiwi

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Its more likely to be an electroplate fault but to be sure it needs to go on STAR (or another MB specific code reader) to have the codes read.
You can throw parts at these till the cows come home and not get anywhere - far better to read off the data properly.
 
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CloudSurferUK

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Its more likely to be an electroplate fault but to be sure it needs to go on STAR (or another MB specific code reader) to have the codes read.
You can throw parts at these till the cows come home and not get anywhere - far better to read off the data properly.

I assume an OBDII reader wouldn't show anything then?
 

John Laidlaw

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STAR or icarsoft 980 or MBII probably but other code readers may not work
You could change the fluid but if it turns out to be as LK suggests you may end up having other work done, and ATF fluid changed again, it’s not cheap. Better getting it read. Where are you based?
 
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CloudSurferUK

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STAR or icarsoft 980 or MBII probably but other code readers may not work
You could change the fluid but if it turns out to be as LK suggests you may end up having other work done, and ATF fluid changed again, it’s not cheap. Better getting it read. Where are you based?

Yeah, that is what I am trying to avoid. Think def needs ATF fluid changed as looks like it has never been done. But wondering if its worth just getting it all done at the same time. Car is 150K now.

I'm in Cardiff, in touch with a company called Continental Cars who can read STAR apparently.
 

LostKiwi

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Take a trip to Bristol to see Steve at Avantgarde. He knows MBs inside and out and is probably the best tech you'll find withing 100 miles of where you are.
 

rf065

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2. On dispstick ATF fluid was black but still translucent (isn't ATF fluid red?)


Mine is yellow in colour, last changed by MB Dealer around 2008. Definitely should not be black.

Russ
 

Wighty

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Yeah, that is what I am trying to avoid. Think def needs ATF fluid changed as looks like it has never been done. But wondering if its worth just getting it all done at the same time. Car is 150K now.

I'm in Cardiff, in touch with a company called Continental Cars who can read STAR apparently.
If you are vaguely handy , you could drain the ATF via the sump plug and then add 3.5L of Fuch ATF 4134 from eBay (maybe £30-40) . If this sorts out the problem , then you can change the ATF fluid and filter , and treat the first experiment as a partial flush .
As others have said Star is usually the first and best approach . The advice above from me is what I would do because I like tinkering and would try avoid the Star payment (if it didn't involve a large experimental cost )
 
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CloudSurferUK

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If you are vaguely handy , you could drain the ATF via the sump plug and then add 3.5L of Fuch ATF 4134 from eBay (maybe £30-40) . If this sorts out the problem , then you can change the ATF fluid and filter , and treat the first experiment as a partial flush .
As others have said Star is usually the first and best approach . The advice above from me is what I would do because I like tinkering and would try avoid the Star payment (if it didn't involve a large experimental cost )

I am confident to do any work, to be honest (did a Toyota apprenticeship many years ago), and your approach is kind of what my initial idea was as well as changing the pilot bushing as its infamous. Like you say, not going to hurt and if problem still exists then not really lost anything other than about £40 for the fluid.

If problem still persists after that will stick it in somewehere for a diagnosis.

But then the more I read, the more confident I am its the electroplate as its always under hard acceleration when it stops changing up.
 

umblecumbuz

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This fault showing up under hard acceleration could even be caused by low fluid.

As your fluid hasn't apparently been changed in 150k miles, and you've got yourself a pilot bush (I'm guessing that's what you mean when you say 'plug with the O rings'), it would be sensible to buy an Atf dipstick to check its level. Around £8 on the Bay. Did you buy the pilot bush because you suspect the old one? Is there any sign of leakage around it?

Changing fluid and filter is a must at this stage in any case, but the dipstick will confrm any low fluid condition before you do so, and may give a clue to the malfunction on hard acceleration.

ATF LEVEL CHECK
Get gearbox up to temperature, keep engine running, sit car on level ground, use Atf dipstick. Readings are obvious.

There are stickies on here for this work, as well as for changing the pilot bush with minimum fluid loss, and for changing the fluid and filter, as well as for the electroplate (conductor plate) - all with photos.
 
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CloudSurferUK

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This fault showing up under hard acceleration could even be caused by low fluid.

As your fluid hasn't apparently been changed in 150k miles, and you've got yourself a pilot bush (I'm guessing that's what you mean when you say 'plug with the O rings'), it would be sensible to buy an Atf dipstick to check its level. Around £8 on the Bay. Did you buy the pilot bush because you suspect the old one? Is there any sign of leakage around it?

Changing fluid and filter is a must at this stage in any case, but the dipstick will confrm any low fluid condition before you do so, and may give a clue to the malfunction on hard acceleration.

ATF LEVEL CHECK
Get gearbox up to temperature, keep engine running, sit car on level ground, use Atf dipstick. Readings are obvious.

There are stickies on here for this work, as well as for changing the pilot bush with minimum fluid loss, and for changing the fluid and filter, as well as for the electroplate (conductor plate) - all with photos.

Yep, as mentioned in the OP I had dipped the ATF oil and level was bang on the line at temperature.

I think im going to change the pilot bush (as i have one) and drain and refresh the oil. As wighty said, nothing to lose as it can always be seen as a flush if the problem still exists afterwards. Then will look at the code reading & electroplate options.
 

Yugguy

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Howdo. If you do take off the sump plug it's 20nm torque when you put it back

If you end up doing a full change (well full less the converter) here's the steps I've created for when I do it, from researching on t'internet. I've bought a 15 quid infrared thermometer to point at the sump to get the temp but if you go for a good 1/2 hour it should be about 80 degrees. I got the kit from MB newcastle on ebay and it included a red top plug seal, new bolts, filter and gasket.

  1. Check all pan bolts – can they be loosened?
  2. Run to warm. Check level with engine running, in Park for comparison to later.

  3. drain for a good 10 minutes

  4. Make sure ALL fluid collected.

  5. sump Pan off, drain filter into collecter.

  6. Clean pan, gasket rim etc.

  7. magnet back in place.

  8. fit new filter.

  9. sump pan on – pan bolts torque 8nm

  10. Drain bolt on with new washer – torque 20nm

  11. measure old fluid. Add same. put filler plug on but don’t seal.

  12. drive around 30 mins to get up to 80deg.
  13. check level, add if needed – engine running, in Park.

  14. up again, check for leaks.

  15. if all ok, undertray on.

  16. seal top filler plug with red plastic thing.
 

Wighty

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If you bevel the edge of the red tab , it allows easy removal for another recheck in a couple of weeks (for those of us with issues :D)
 

umblecumbuz

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Step 5 above needs a caution.

However long you drain, there will still be a fair amount of atf left in the sump pan. Take it off in stages, by removing front bolts, progressively loosening rear bolts, tilting and assisting drainage as you go.
Saves a mess on the floor and down your overall sleeves!
 

Westheath

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ATF if its really black I wouldn't waste money on changing it, especially if there's a lot of material in the drained fluid,
usually it makes the gearbox worse as all the particles floating around in the oil have now gone and the fresh fluid cant grip the clutch plates.

Put the old fluid back in after draining and inspecting don't waste your money on new ATF.

I would get a recon box and TC fitted.
 
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CloudSurferUK

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Well for those interested, had the codes read today at Continental Cars Cardiff (Matt was very helpful & knowledgeable!) and it came back with a speed sensor failure so its Gearbox service and Electroplate time! Ah the joys!
 


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