CVT Gearbox - A Class

[kwakdonut]

Hello all,

we are having an ongoing problem with our A Class's CVT gearbox that has so far been back to MB twice - first part replacment was the valve body, second was the torque converter.

The problem we have had is 'slow' shifting, eg the gearbox does not change up or down quickly and makes you feel like you're in the 'wrong' gear. (Bit like pulling away in 3rd).

It seems better now but we are still having problems at low speed, between 20-30 mph where we still get this awful rumbling like the car is in the wrong gear. It can be overcome by putting your foot down but this kind of defeats the object of economical driving!

Anyone else had this problem or come across it before?

I have search through the forum but it seems that normally, the CVT box is pretty reliable.

Car is W169 180CDi

Any help welcomed - it goes back into the stealers later this afternoon, again!

 

[grober]

Has it got a dual mass flywheel? Lots of faults with these on high torque diesel models. Don't know if this applies to automatics or restricted to manual gearbox cars only? good introduction to the technology here. http://www.schaeffler.com/remotemed...library/downloads/luk_fail_diag_zms_de_en.pdf

 

[kwakdonut]

Hmmmm, not sure. MB Swindon have been pretty damn helpful so far and their techie has been pretty sure what was wrong (he said torque converter but MB said no at first!).

It is improved but not how it was for the first few months we had the car. The CVT gearbox is lovely and smooth when working correctly. It is to a point now but it still doesn't feel 100%.

Every scrap of help is welcomed!!

 

[BlackC55]

It is not somthing I have come across either. Normally they are 100% reliable. I would be interested in the result to fix it

 

[Smatt]

No probs thus far with our Turbo-ed CVT, but only clocked about 6000miles
A lot of comments about CVTs on here generically being a bit negative in other brands, but I am not aware of specific MB CVT problems being posted over the last 1yr

 

[kwakdonut]

No, must admit one of the reasons we bought this particular model was the reliability of the gearbox.

It's so annoying because the fault now is so small but might warrant an actual gearbox change to fix it!!

Might see if MB have another CVT box vehicle that we can try to see what it 'should' be like.....

 

[Buggerlugs]

It seems better now but we are still having problems at low speed, between 20-30 mph where we still get this awful rumbling like the car is in the wrong gear. It can be overcome by putting your foot down but this kind of defeats the object of economical driving!

Hi Kwak,

The rumbling initially suggests that the torque converter lockup clutch is "hanging" in the applied position at inappropriate times. This would normally be attributed to a converter or valve body fault, but being as they've supposedly been replaced already.............The next most likely candidate would be a fluid crossleak in the torque converter stator tube assembly, it could be simply a defective seal ring or even the stator tube itself can be damaged slightly causing a seal misalignment/poor performance. To confirm this a gearbox strip on the input side would be required, during this process the TC housing to maincase gasket would be checked for another possible cause, a blowout of the gasket itself between the oil passages.

One thing you can be pretty certain of, if the problem is indeed a tangible hydraulic fault, then it will become progressively worse over time.

 

[kwakdonut]

Hi Kwak,

The rumbling initially suggests that the torque converter lockup clutch is "hanging" in the applied position at inappropriate times. This would normally be attributed to a converter or valve body fault, but being as they've supposedly been replaced already.............The next most likely candidate would be a fluid crossleak in the torque converter stator tube assembly, it could be simply a defective seal ring or even the stator tube itself can be damaged slightly causing a seal misalignment/poor performance. To confirm this a gearbox strip on the input side would be required, during this process the TC housing to maincase gasket would be checked for another possible cause, a blowout of the gasket itself between the oil passages.

One thing you can be pretty certain of, if the problem is indeed a tangible hydraulic fault, then it will become progressively worse over time.

Thanks for that - someonewho appears to know the insides of the CVT gearbox! I shall print off your comments and offer them up to MB Swindon - see what they think.

Wifey has done just over 100 miles since they replaced the TC and it seems to be ok although the stealer has taken the car in anyway to do another further set of checks.

I shall report back once we get the car back!!

 

[kwakdonut]

OK, final report back for those who were/are interested!

Gearbox is now 100% ok again - looks almost certainly like the torque converter was faulty and was replaced with a modified version. The 100-odd miles between fitment and the gearbox being ok again appears to have been a 'running-in' come 'learning' process and has been fine ever since.

My thanks go to those on here that offered help and advice and to Richard and Mark @ MB Swindon who were probably thoroughly pi$$ed off with me and my wife by the end of this but didn't show it!!!

Another plus was that we had a lovely, 09 plate CLK 280 Cabriolet for the best part of 3 weeks!

 

[philangst]

Just found this post and my 05 A-Class diesel CVT does the same. Its quite hard to describe and doesn't happen all the time, sort of jerky/rumbling hesitation like its in the wrong gear. I would agree its between 20-30mph and evident when you go round roundabouts. If you put your foot down it stops and it doesnt seem to happen when the engine is cold (1st 10 mins) but after its warmed up the changes are less smooth!

 

[dokalj]

ML163, 2003 ML270 CDI Gearbox Oil

Hi,

Does anyone know where I can find the location to check the gearbox oil and then top up if required? Does the vehicle have a dipstick for the gearbox?

Hope someone can help

dokalj

 

[lynall]

You would be better doing a search, your gearbox is a 722.6, car has a dipstick tube but no dipstick you have to get them from either dealer or e bay about £20.

Bear in mind the a class will fit in your boot



Lynall

 

[dokalj]

You would be better doing a search, your gearbox is a 722.6, car has a dipstick tube but no dipstick you have to get them from either dealer or e bay about £20.

Bear in mind the a class will fit in your boot



Lynall

How often do you suggest changing the gearbox oil?

dokalj

 

[Falelza]

Just found this post and my 05 A-Class diesel CVT does the same. Its quite hard to describe and doesn't happen all the time, sort of jerky/rumbling hesitation like its in the wrong gear. I would agree its between 20-30mph and evident when you go round roundabouts. If you put your foot down it stops and it doesnt seem to happen when the engine is cold (1st 10 mins) but after its warmed up the changes are less smooth!

Have exactly the same problem on my 05 A-Class diesel CVT. Seems to be worse in C than S. Local Merc repear centre has now identified the problem as being the torque converter. Waiting for parts to arrive. Will see what the outcome is once replaced.

 

[philangst]

Have exactly the same problem on my 05 A-Class diesel CVT. Seems to be worse in C than S. Local Merc repear centre has now identified the problem as being the torque converter. Waiting for parts to arrive. Will see what the outcome is once replaced.

Yes I've been running mine in 'S' mode recently because it seems to reduce the judder effect somewhat. Can you let me know if the replacement parts fix the problem and how much it costs. Ive got some after market warranty which 'may' cover it!! I think I can live it until it needs a service (2k miles or so) if it doesn't get worse. I will take it to my local Indie.

On a different subject my car rattles badly at first on cold mornings (<10 degrees) but its fine when its milder. Is this normal

 

[philangst]

Took my A Class auto to local Merc Indie today for a service and mentioned the transmission problem. He hooked it up to the STAR diagnostic but there were no stored or current fault codes for the gearbox. The ATF was a 1 litre down on what it should have been so he will top up later this week (has to order) and see if this improves it, otherwise it needs to go to an auto-box specialist, something about 'hub fault' was mentioned which he said could be expensive. Its not terrible, I just think it should be a lot smoother

 

[Corona]

My brother's 2007 A200T gearbox stopped working completely. It doesn't go to D nor R, when you put it on R the reverse lights go on but nothing happens.
Any ideas?

 

[uberpoman]

Just found this post and my 05 A-Class diesel CVT does the same. Its quite hard to describe and doesn't happen all the time, sort of jerky/rumbling hesitation like its in the wrong gear. I would agree its between 20-30mph and evident when you go round roundabouts. If you put your foot down it stops and it doesnt seem to happen when the engine is cold (1st 10 mins) but after its warmed up the changes are less smooth!

Hi there,
Having pretty much exactly the same problem as described above. I have a 2005 A-Class Petrol Auto.
Looks like it could require a new torque converter? Can anyone who's had this problem repaired give me an indication on price for a fix?

Thanks

 

[bcvale]

CVT A200cdi

Hi there,

I have the same vibrations on my A200cdi (2005) while on roundabouts in D, though if I rev it up it stops. (1)

Also have experienced a sort of grinding noise after a few km when the gearbox shifts down which increases with the revs. (2)

My car now has 242 000 km (~150400 miles) and the problem (1) has never been worked out but (2) was temporarily solved with a previous gearbox maintenance that supposedly changed a few bearings and is now returning.


Any solutions for the vibration problems?

Thanks

 

[grober]

There have also been problems with the drive shafts of this model . If the car's symptoms only appear when cornering then this might point in this direction rather than gearbox?