9G Auto Gearbox stays in 2nd gear when moving slowly

[gigdesigns]

I have a W205 with a 9-speed auto gearbox.

One real niggle I've noticed is when I am crawling along very slowly, say up to a junction, the gearbox will stay in 2nd gear, even when I am doing 1mph.

When I get to the junction and then decide to accelerate, I'll start to move forward but then it decides I should be in 1st gear and there's a noticeable hesitation while it shifts gears and then jerks ahead once engaged. Really annoying when you want to quickly pull out, particularly at a t-junction and not very comfortable and becoming of a Mercedes!

And it's not that I am flooring the throttle, this happens during normal sedentary driving around suburban roads.

The gearbox will only shift down to 1st once the car has come to a complete stop. You can however still be moving very slowly forward with the speedo reading 0 and the wheels slowly turning and the gearbox stays in 2nd and only changes down once you start to accelerate.

Does anyone else notice this annoying habit with their gearboxes?
Maybe it's only an issue with the 9G speed box?
In my opinion it should be changing down to 1st when you're going 1mpg or less.

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[GeeJayW]

A feature of Comfort mode perhaps?

Nick it into Sport mode if you want a quick getaway.

 

[grober]

May depend on whether the car is in E or S mode? In economy mode Mercedes always used to default to second gear starts. Otherwise its probably some "fiddle" to achieve the lowest emission levels as defined by some specific EU emissions driving cycle criteria?

 

[st13phil]

I take it you're driving in Comfort (or ECO, depending upon what it's called in your car) Mode? If so, then 1st is only used if you boot it. If you want it to use 1st in normal driving then switch to Sport mode.

 

[gigdesigns]

Yes, Agility mode is set to Comfort Mode.
Options are Eco, Comfort, Sport, Sport+ and Individual.

The gearbox does the same thing Sport mode. In Sport+ it shifts to 1st earlier so no issue there.

The thing is I'm not booting it, I'm driving normally.
Maybe I have a heavy foot and it's just something I need to adapt to.

 

[ManiacGT]

Behaviour not befitting a mercedes? You should try the 7G+ I have in my C200 S205. Borrowed from the 90's, the worst transmission ive ever owned.

 

[GeeJayW]

Have 7G+ in our (S205) C250d Prem+ and had the same in our previous car (C204) C220d. While I've never been a fan of auto boxes, I've been happy enough with my 7G+ experience so far. My daughter has 9G in her (S205) C220d Premium and that seems ok too.

All auto boxes that I've driven over the years struggle in some areas, particularly at low speed going tip-out to tip-in.

 

[Bobby Dazzler]

Behaviour not befitting a mercedes? You should try the 7G+ I have in my C200 S205. Borrowed from the 90's, the worst transmission ive ever owned.

I'd get it looked at. The 7G/7G+ is no ZF8 but it's still pretty good. If it's that bad, then it's worth following up. When was the transmission last serviced?

 

[ManiacGT]

On the diesel I've driven it's acceptable. On every petrol (like mine) shifts are very poor.

It's had updates and adaptations galore but as I've replicated the issue in dealer petrol C200s it's a design issue not my car alone at fault.

Frankly it's garbage. My car is 2 years old and sadly I missed out on the 9 speed by a few months.

MB say the jerky and rough shifts are normal and a feature (LMFAO) of this transmission. It's like someone stabs the brake on every shift. Worst drivetrain I've ever had, a waste of £18000 by the time I hand it back. First and last MB for me. Fed up.

 

[GeeJayW]

When we test drove the SLK200 (R171), it was an auto. Didn't like it, but liked the car so bought a 6-speed manual version. Like that a lot and kept the car for seven years. Also drive an SLK 350 with 6spd manual, like that a lot too.

Then got to test drive an SLK250 (R172 petrol). That had the 7G+ auto. Didn't like it much, but again thought it was a nice car.

So yes, could be that 7G+ is better on the diesel variants. Our current car changes very smoothly. Most of the time especially if some music is playing, don't really notice the gear changes at all.

 

[Headhurts]

I have an E350 S212 with the 9 speed box.

This is much better than the previous 7G box which was not bad either.

On the odd occasion this does happen you come slowly up to a junction or roundabout and decide to nip out but the car hesitates unless you use kickdown.

It does not do it all the time just occasionally but far less than he 7G box.

I put my car in sport mode virtually all the time, it's difficult to replicate it just seems like the box is being very lazy.

My car has done less than 9000 miles and is 1 1/2 years old so doubt there are any issues with oil etc.

I have seen a couple of threads on this before on this or the other forum.

Robin


Sent from my iPad using Tapatal

 

[flowrider]

On the diesel I've driven it's acceptable. On every petrol (like mine) shifts are very poor.

It's had updates and adaptations galore but as I've replicated the issue in dealer petrol C200s it's a design issue not my car alone at fault.

Frankly it's garbage. My car is 2 years old and sadly I missed out on the 9 speed by a few months.

MB say the jerky and rough shifts are normal and a feature (LMFAO) of this transmission. It's like someone stabs the brake on every shift. Worst drivetrain I've ever had, a waste of £18000 by the time I hand it back. First and last MB for me. Fed up.

You must have an issue with your gearbox, i have had Mercedes auto's since 2009 and all have been very smooth (2 ML's and an SL).

 

[Bobby Dazzler]

On the diesel I've driven it's acceptable. On every petrol (like mine) shifts are very poor.

It's had updates and adaptations galore but as I've replicated the issue in dealer petrol C200s it's a design issue not my car alone at fault.

Frankly it's garbage. My car is 2 years old and sadly I missed out on the 9 speed by a few months.

MB say the jerky and rough shifts are normal and a feature (LMFAO) of this transmission. It's like someone stabs the brake on every shift. Worst drivetrain I've ever had, a waste of £18000 by the time I hand it back. First and last MB for me. Fed up.

Has it done it since day 1? Has it got better or worse through time? It really doesn't sound right.

 

[ManiacGT]

When I first received the car it felt like someone tapped the brake on each shift. It was bad.

Many updates and miles later it's still a bit jerky esp when cold but is improving over the miles.

As mentioned previously I've replicated this in other dealer petrol C200s so it's not just mine.

Diesel versions seem much better and more what you'd expect of an auto.

I, the dealer and MB have spoken many times. I'm told this is as good as it gets.

 

[Deletedmember130310]

What was the gearbox like car you test drove before placing your order?

 

[GeeJayW]

What's it like when driven 'with purpose'?

One of the problems with small capacity, boosted gasoline engines is the relatively weak off-boost torque curve. This is highlighted on up changes. It's not really an auto gearbox fault, more a feature of the overall installation.

 

[ManiacGT]

My experience is on light throttle and WOT it's relatively smooth (albeit at WOT you feel the torque loss during changes quite a bit). It's mid (every day) throttle levels that are the most snatchy.

The car I test drove was first a diesel which was ok then a petrol that I didn't note had particularly bad changes but then on the test drive it was just a pootle around the locality.

 

[timskemp]

I have had a few now. 5G e270 was smooth all the time. 7g c320 CDI was mostly smooth but could be harsh if you were hasty at junctions. 7g+ e220cdi was fine all the time, a little rough when very cold. 9g e220d is fantastic but yes it does hold 2nd to a standstill if not in sport+. Doesn't bother me at all.

My slk 200 is also a 7g+ and I have no problem with its shifts. In E it is smooth as long as you use light throttle openings, in S it really wakes up.

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[David404]

I've got the 7G and yes it hesitates when applying throttle as the box downshifts but for me its a small price to pay against a manual transmission that needs constant attention. Never going back to a manual box.

 

[gIzzE]

ManiacGT, have you got the dealer to reset the gearbox adaptions?

It might even be worth finding a local place to do it rather than the dealer.


It is not the gearbox, I have that gearbox in the E350, but that is NA and I think that is your problem, I think it is the car coming off boost when the gear change happens that gives you the jolt.
I would guess Mercedes have not programmed the gear change at the right point in the torque curve, which is something that they might no be able to sort, hence why it is still doing it after new software.

What revs does it change gear at when you are cruising around?

The height of the torque curve on your car is around 2800rpm before dipping sharply, if the gear changes at this point I would expect a bit of a jolt.

You might find that a remap works wonders, someone who knows Mercs well can map it for smoother gear changes, this is often advertised.