Mercedes CLS Gearbox Mystery - Can you Advise Please?

[RussMarsh]

Hi there, I am new to the forum and see there are a lot of helpful people on here. I am looking forward to being a regular contributor and certainly will help if I happen to know something about a problem if I have any experience of it

Background:
My CLS (auto) had done about 50,000 miles and I thought it would be a good idea to give it a gearbox oil change (Before you all jump on me I know now I should have left well alone.. I thought I was doing a GOOD thing!

So I asked a local garage to do the job and I bought the oil and filter kit myself..

Now then - the gearbox when cold seems to slip. You have to sometimes really rev it to get the car moving - I have looked this up and it seems it could be a few things but garages are VERY reluctant to even look at it..

• The above problem ONLY happens when the car is cold (first drive of the day)
• The gearbox makes no noises and never jumps out of gear or anything like that
• When I arrived at a guy's who said he would look at it the car was warm - he took it out and declared the gearbox was perfect. I had driven on the motorway about 20 miles to get to him and the car flew down the road at 80+ with NO issues at all - I could even shift the gear lever to the left to change it down and to the right to shift it up - no problems at all.

Could it be the level of the oil in the gearbox? - it does say that here:
Transmission Slipping Signs
If your transmission slips only when it's cold, then there could be three possible reasons. The first one could be that your engine is low on transmission fluid and could use some more. The reason it works fine once it's warmed up, is because the oil expands with heat. The second reason could be that the fluid has become old and denatured, and needs to be changed. Remember to use only the genuine transmission fluid when you replace it. The third reason could be that the oil has become dirty or contaminated, which again needs to be changed. If it's dirty, then you could also check your filter and replace it, if needed.

ANY help or suggestions would be more than welcome please guys. Also I live near Burnley, Lancashire in the UK so if anybody knows someone who would be at least prepared to take a look then that would be great!

 

[clk320x]

Before you all jump on me I know now I should have left well alone.

You did the right thing

 

[Trickythemerc]

You need to have the fluid level checked with the proper length dip stick, did you buy the right spec fluid and how much did the garage put in. What gearbox do you have 5 or 7 speed ? They use different fluids that are not compatible with each other.

 

[RussMarsh]

Hi guys, thanks for being so quick ;-)
I used a proper parts supplier and it was the correct gearbox oil kit for the car so they said - it's a 7 speed - I can't remember exactly how much I bought for them to put in now - maybe 6 litres? - Obviously I didn't watch them put the oil in so I don't even know if they used it all - I just assumed...

Are we thinking it could be the oil level? - I need to find someone who's not scared to death to check it out for me I think - but it's hard finding someone..

 

[Trickythemerc]

The seven speed box is best left to a Merc specialist to service, they are a bit tricky to fill to the correct level and may need to have a star session to get things right. The early boxes suffer from clutch wear and need adjustments done using star. I believe there were ten increments for adjustment then it increased to twenty due to more rapid wear taking place. A star session should give all the info and fault codes needed to sort it out.

 

[zipdip]

Well I suspect your box does not have a dip stick,I assume it is the same box that is in my S320 it is 7 speed,what has to happen is that with the car level and up in the air the engine is started to warm up the gearbox oil,with a star diagnostics on it when it gets to the right temperature then the level can be adjusted,as Trickythemerc said,if you go to a indy he will be able to adjust the box if needed.

 

[DSM10000]

As said, find a local MB independent specialist.

A full fluid change on the 7 speed gearbox is around 8 litres. Do you have the oil specification on an invoice?

Regardless if the fault has appeared after the work was carried out then the garage that carried out the work are responsible.

 

[ToeKnee]

Regardless if the fault has appeared after the work was carried out then the garage that carried out the work are responsible.

Would the garage also be responsible if the customer gave then 6l of fluid, which they used, and the box needed 8?

 

[DSM10000]

Yes. As a garage they have a duty of care to ensure any parts etc they fit are suitable in terms of fit and quantity regardless of the supplier

If you gave a garage 4 lites of oil for a service and your car required 6 would you find it acceptable if they only added the 4?

Plus I I imagine they didn't drain the torque convertor and cooler fully

 

[daveenty]

Also I live near Burnley, Lancashire in the UK so if anybody knows someone who would be at least prepared to take a look then that would be great!

If Bury isn't too far for you then I can recommend JBM who's a good man with Mercedes and the only person I let touch my little 190E.

If he can't fix it then he'll put you in touch with an automatic specialist just round the corner, who's name escapes me at the moment.

 

[Petrol Pete]

It will need about 5 or 6 liters for a basic ATF change , more like 8.5 liters if the torque converter and cooling system was drained as well. At 50K miles it is unlikely that there is anything wrong with the gearbox. Fluid level needs to be checked with the fluid at 80 degrees Celsius by someone who knows how to read the (correct) dipstick.

Do not take a chance guessing the oil level. Disaster lies that way.

 

[DSM10000]

I believe temperature is around 45 degrees Cfor the 7 speed
'box and 80 Deg C for the 5 speed

 

[steveq]

Fluid level needs to be checked with the fluid at 80 degrees Celsius by someone who knows how to read the (correct) dipstick.

Do not take a chance guessing the oil level. Disaster lies that way.

There is no dipstick or even a dipstick tube on the 7G gearbox.
It is filled by pumping in fluid through the sump drain hole; running the engine to get the gearbox up to the required temp; let fluid out through the sump drain until it stops.
It is difficult check the fluid level between gearbox services.

 

[stephenmercedes]

Yes. As a garage they have a duty of care to ensure any parts etc they fit are suitable in terms of fit and quantity regardless of the supplier

That is exactly why a garage I used for another car (not Mercedes) changed their policy after me supplying them parts for years by not allowing customers to supply any parts, they would only fit/use products they sourced. I thought at first it was just a 'money' thing as they lost out on margin on parts, but was told that the law had changed making them responsible for any parts fitted, whether they supplied or not...

 

[NDFR]

Mercedes Newcastle on their eBay shop could be your go to place for genuine Mercedes service items/ spares. Give them your reg and they will send out the same day anything you require. They are usually very well priced too.

 

[Petrol Pete]

That is exactly why a garage I used for another car (not Mercedes) changed their policy after me supplying them parts for years by not allowing customers to supply any parts, they would only fit/use products they sourced. I thought at first it was just a 'money' thing as they lost out on margin on parts, but was told that the law had changed making them responsible for any parts fitted, whether they supplied or not...

Now I know why I saw a mechanic at my indie doing just that to an MB on the lift, I did not know that was one of the differences between a 5 and 7G

 

[Gregor]

Hi there,
I have CLS 2006 (56) 97k for last 6 years.

I have changed gearbox oil at 56k and 85k.
It didn't help with any problems at all. I had similar experiences.

The problems mostly occur during winter and/r as you said when very cold.

Will be honest with you man, as Trickythemerc said early version of 7G are prone to those problems.


I currently experience another level, which is clutch disengage after breaking from high speed to low speed (motorway to slip road). Apparently repair of vales and electronic might help but it's massive hassle - check those guys https://www.softelectronic.com/
Before I could just switch to neutral and back in gear and it fixed most of problems but now with "clutch" - i had to switch off and on engine.

So in general I got the feeling it's not if it will happen it's just matter of when and that's the main reason (other lack of folding rear seats) I made a decision to sell mine. It breaks my heart but well I could always get a 2008 up model ))) but will I?

p.s. I replaced the turbo and sensor which had some impact on jerky acceleration and locking gearbox in particular gear like 2 or 3.

 

[markjay]

In addition to all that has been said above...

The early 7g autoboxes and the later 7g+ autoboxes use different types of ATF.


Also, filling-up is done via the drain plug... and level checked via STAR.

On the 7g+ there should be a drain plug on the torque converter so should not be an issue to drain most of the ATF.