W169 - CVT problem ?

[blackpool]

Hello Guys

I have a W169 CVT petrol 2005 and I have noticed a peculiar problem that happens every now and then. It tends to happen at low speed, either when setting off on a roundabout or after negotiating a corner. Basically the car jumps several times, the engine seems to momentarily race with each jump and then the revs drop off. Has anyone experienced anything similar?

Many thanks in advance.

 

[mauno]

last time gearbox fluid change was at?

 

[danclyon]

last time gearbox fluid change was at?

As with all CVT - absolutely VITAL on or before the miles stated (preferably before!!) otherwise it gets expensive!!

 

[mauno]

also only the stated liquid type,no other type should be used at all even if it is expensive.look in the servicebook for the change date

 

[blackpool]

Just checked the service book and the change is specified at 40k. The car has done 41k but a dashboard reminder would have been handy! What is the point of having a computer which tells you Service B etc in 6000 miles and forgets to remind you that it needs Service 20 in X miles? Also helpful (not) of MB to class the gearbox oil change as Service 20, right at the end of all the service requirements and after 60k service requirements etc. Will get it changed asap and report back. No warning lights though so it may be something else but thanks guys.

 

[mauno]

that will never give you a warning light.just when something inside completely gets screwed by the worn liquid

 

[npuk]

Has the car been serviced at the main dealer? There was an update for the CVT ecu that may have been missed if the car hasnt been at a main dealer for some time.

In my service book ATF change is listed at every 60,000km so about 37k miles.

 

[blackpool]

Hi npuk, the car had a diagnostic check at the main dealer about 6 months ago in relation to another issue but its not been serviced at MB for a couple of years. So the update may have been missed so I will look into that. Thanks for that.

 

[blackpool]

Npuk, do you know if there will be a technical bulletin on the CVT ecu update on WIS/ASRA? Or is there any other way I can details on (and the reason for) the update?

 

[danclyon]

In my service book ATF change is listed at every 60,000km so about 37k miles.

The UK docs state 37,500 - for me that's 35k - or every 2nd service (which seems to be about 35k miles on SWMBO's car)....

 

[mauno]

The UK docs state 37,500 - for me that's 35k - or every 2nd service (which seems to be about 35k miles on SWMBO's car)....

you know it!!

 

[blackpool]

The service booklet states 40,000 miles (photo attached for confirmation) and if it was THAT critical - the onboard computer should warn you. It warns about oil services and my point was - it should also warn about the ATF too.

 

[npuk]

Mine says 60,000km too but the service book is different from yours so the post facelift has a different service book. Also a 2005 car would be on ASSYST PLUS where as after 2007 they would be on ASSYST Fixed.

Regarding the CVT update there will be a technical bulletin but I dont have the number sorry, try a google search.

 

[danclyon]

Mine says 60,000km too but the service book is different from yours so the post facelift has a different service book. Also a 2005 car would be on ASSYST PLUS where as after 2007 they would be on ASSYST Fixed.

Regarding the CVT update there will be a technical bulletin but I dont have the number sorry, try a google search.

The dealer told me categorically that the recommended change interval is 37,500 miles NOT the 40,000 listed in the book - and their records support that too. It would appear that the guidance was pulled back in be 2500 miles at some point and the 37,500 was ABSOLUTE maximum - they recommended actually pulling it back in towards 30k. For me, every 2nd service is what the equates to....same as for my Audi with the same type box.

Just sharing what I was told.

FWIW, Audi's official change interval is 40k miles, however they too at the dealers recommended every 2nd service (which for me is typically about 32k miles).

So, the message seems to be "sooner"...

D.

 

[mauno]

makes sense as on nissan cvt the recommendation is 35000 miles.

 

[blackpool]

It would have been handy if MB had mentioned the need for a fluid change when the car was at their workshop 6 months ago.

Moooooving on - I believe the system needs depressurising before the fluid is drained. Does anyone know what needs to be done?

Also some confusion about the amount of fluid needed - Merc says 5.7L for transmission only, 6.0L with torque converter but then contradicts itself and says only 4.0L if the torque converter is not lowered? Which seems odd beause the first two figures imply the torque converter only holds 0.3L.

 

[mauno]

also need to be at operating temperature!

 

[blackpool]

Yes - but need to know how to depressurise first

I also have a BMW with air levelling suspension and to depressurise that you simply disconnect the battery and unplug a hose so hoping its something similar for the CVT - but need to know the specifics.

 

[mauno]

nothing like that.pop the top cap off.thats it

 

[blackpool]

Really? Just seen this and it mentions 200 bar of pressure - hence my concern.