7G gearboxes

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Pitts Pilot

Active Member
Joined
Mar 11, 2012
Messages
698
Location
Near Folkestone, Kent
Car
SL63 AMG 6.3, VW Tiguan 2.0
This is about the shi4y 7G gearboxes that Mercedes Benz-the-truth pass off as automatic transmissions.

I'm not alone, there have been several threads on this Forum lately regarding jerky 7G transmissions, both the 722.6 and the 722.9.


I started a thread regarding the occasional neutral I got when the box on my SL was cold, and others have complained about "Jerkiness".

Well MB this is not good enough.



Not happy with the "Box full of neutrals" I was occasionally getting even after a recent B service and change of transmission oil MB Basingstoke did, I booked the car in with MB Wandsworth.

MB Wandsworth reported no fault codes (as did MB Basingstoke by the way) and could find nothing wrong.

OK I said, I'll video the 'box full of neutrals' the next time it happens and they said "Great, but we will need significantly more to persuade the Warranty department to agree to change the valve unit (the main candidate for causing the problem)." Great. That's encouraging; NOT.


So with low fluid levels on my mind I went to see Olly at PCS.

Had the oil been changed at the B service, and was the level correct? Answer: YES to both questions, so fair play MB Basingstoke.



Now, since Olly dropped a splash of oil from the drain plug I've got the 'Jerky blues' too!

First couple of gears the car lunges forwards with as much smoothness as the sharp edge of a broken bottle.

What the Fook is going on NOW?


The car has done 38K and takes off with all the precision of a learner driver's first lesson on how to use the clutch.

I don't know exactly how little oil was removed from the gearbox with the "Splash" that Olly used to check the level and the colour, but how can a modern transmission be SO sensitive to oil level?

The answer to that is of course it's not the oil level, it's the valve unit that controls the gear changes.


What makes my blood boil is MB's childlike innocence regarding the problem.


What are the odds that they have seen this problem on other 7G boxes before?
Pretty high I suspect, or am I and a few others on this Forum the only owners in the UK to experience problems?

So why the denial and the impenetrable attitude to their warranty scheme?


There is a genuine problem with some of the 7G transmissions, so MB, stop the "What? You have a problem? We can't find anything wrong" approach, and admit there are customers/owners out there regularly experience whiplash when they set off each morning.


So what to do? Well, for me it's back to MB Wandsworth. Leave it overnight so it's cold the next day. But this time, I'll be there as they open up, and I'll make sure that the car is not moved (and thus warmed up) by a car park guy moving it before a senior mechanic gets to test drive it.

I also intend to call MB Warranty on Monday morning and chew their ears off about false neutrals and jerkiness. If enough of us do this, it WILL make a difference :)

Rant over :)

Robert
 
Looking forward for your updates on the issue.
 
It is simply no good ranting at a salesman or whatever all they seem to do is collect there wages at the end of the month....they will probably make things more difficult for you as you have made it difficult for them!

I know not an answer to your problem but this is the main reason i changed from Volvo after 30 yrs to getting my first Merc and although an older one i do believe it is one of the most reliable ...so far!.....later Volvo parts are staggeringly high compared to MB and the motors are always breaking down and unreliable, maybe because they are still mostly Ford`s.

My 7g is ok so far and will only sometimes grab bottom gear on a steepish hill when slowing right up, slowly.

The manufacturers are all at it , some more than others, they all have built in obsolescence in there products and so MB pick the Valve Unit to get some money back to pay for your free coffees or even the Main Dealer being in existence in your town.

Maybe if most owners used the Main Dealer things maybe cheaper but i do doubt that and so i use my independent also, so we only have ourselves to blame and just to get on with it!

I don`t know the MB way of warranty but would of thought after 3 years and to start having MOT`s then maybe up to the owner to just bite the bullet and get the job done and move on.....

Having said all that i do look forward also to your updates...
 
Have you taken the car to them after one of these occurences and not turned the engine off?

I had an issue with the MAF sensor, it came up faultless on each check and the service department told me that the very minor faults would be reset when the ignition is turned off. This definitely was a minor fault but the revs surged when changing down to 1st and this caused the car to lurch forwards, which felt like the car could lurch into the car in front, very unlikely to happen but it was very dis-concerting.

I took it in after it occurred, left the engine running and then within 20 minutes a new MAF was being ordered.

I HATE parts being thrown at a problem so as annoying as it is, it could be worth asking if this is the case with the faults you are experiencing.

Dave!
 
I've owned a few Mercedes with the 7G box, some are jerky in low gear, others are not. The newer 7G plus is on another planet compared to the earlier inclinations though...

If a car did enough to make my 'blood boil' then I'd sell it, it's as simple as that, life's too short to get all worked up over a car.
 
I gave up with Mercs years ago and life has been better ever since.
 
Hope you get it sorted. The 7g in my cls350 cgi petrol is super super smooth, better even than the 5sp clk I had for 6 years. No bother so far.

I've always thought the 7sp work better and have an easier life with the more linear torque delivery of the petrols rather than the diesel equivalents.

Convincing MB to action the warranty can be challenging though.
 
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I've owned a few Mercedes with the 7G box, some are jerky in low gear, others are not. The newer 7G plus is on another planet compared to the earlier inclinations though...

If a car did enough to make my 'blood boil' then I'd sell it, it's as simple as that, life's too short to get all worked up over a car.

This is what I did. A new valve body did not cure the fault and I'm afraid I ran out of patience.

I replaced it with a Volvo.
 

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