Do you rate the 7-g tronic auto box?

Do you rate the 7-g tronic auto box?

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Discussion

italian job

Original Poster:

246 posts

231 months

Thursday 11th February 2016
quotequote all
Thanks for all the informative replys....autoboxes are never cheap are they? Fluid change always sounds like a good idea,i did it on the 530D even though that's supposed to be sealed for life.

donkmeister

8,181 posts

100 months

Thursday 11th February 2016
quotequote all
J4CKO said:
I only use manual to pre select a gear for overtaking, sat behind a dawdler and want to maximise that overtaking opportunity and avoid the short delay whilst it kicks down, drop it into third and then hoof it past.
Me too - the manual mode seems to act as a "range limiter" like the old 1 and 2 on an old style 3-sp autos. I don't know if the later ones or AMG ones are any more "manual" though.
Worth knowing that Comfort mode takes off in second gear (and also uses a higher ratio 2nd gear for winter use).

Jobbo

12,972 posts

264 months

Thursday 11th February 2016
quotequote all
I went from a BMW with ZF 6sp to a W204 C350 CDI with 7sp and currently have a BMW again with the ZF 8sp.

While at first the Merc felt like a step backwards from the BMW 6sp, I still have fond memories of it. It felt a bit like a 5sp with an extra 1st and an extra 5th gear for all the use 1st and 7th really were; but it was always possible to tell which gear you were in and (when using the paddles) whether you wanted to drop one or two gears fairly intuitively. Now with the ZF 8sp I struggle to work out whether I need to drop one, two, three, four or possibly five gears. 7 ratios, for me, seems to be the most I can sensibly distinguish without thinking about it.

The Merc also feels more like a traditional auto box in comparison to the ZF 8sp; the 8sp seems to lock up the torque converter at incredibly low rpm in an attempt to be more DSG-like. That's fine but I quite like the ability of a torque converter to increase the revs a bit almost instantly without changing gear.

I wouldn't have any problem swapping back to a Merc with the 7-sp now, even after living with the 8sp ZF for a while. Although that's me; if you are more of a PDK/DSG fan then perhaps you'd not feel the same.

Derek Smith

45,666 posts

248 months

Thursday 11th February 2016
quotequote all
italian job said:
Thanks for all the informative replys....autoboxes are never cheap are they? Fluid change always sounds like a good idea,i did it on the 530D even though that's supposed to be sealed for life.
Overall, I'm told, automatic cars tend to be cheaper to run than manual box cars over the life of the car.

There is less chance of them being overreved, the engine doesn't labour and they are driven by those who are not boy racers.

Autoboxes can give problems but these are generally through poor use. Towing excessive weight can be a killer, especially if additional cooling of the box is not fitted.

I changed the oil in the gearbox of my 7-g when a plate went and was told that they recommended it at 70k anyway. They also recommended changing the oil in the compressor at the same time, although I had the N/A V6 so not applicable.


J4CKO

41,588 posts

200 months

Thursday 11th February 2016
quotequote all
donkmeister said:
J4CKO said:
I only use manual to pre select a gear for overtaking, sat behind a dawdler and want to maximise that overtaking opportunity and avoid the short delay whilst it kicks down, drop it into third and then hoof it past.
Me too - the manual mode seems to act as a "range limiter" like the old 1 and 2 on an old style 3-sp autos. I don't know if the later ones or AMG ones are any more "manual" though.
Worth knowing that Comfort mode takes off in second gear (and also uses a higher ratio 2nd gear for winter use).
I believe the AMG manual mode doesnt change up at max revs like the non AMG ones do, other than that, I think they are the same, perhaps with slightly different tuning.


jamie w

175 posts

171 months

Thursday 11th February 2016
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donkmeister said:
Worth knowing that Comfort mode takes off in second gear (and also uses a higher ratio 2nd gear for winter use).
My E320cdi always starts in first in C or S mode. I think I've read somewhere that it's only 6 & 8 cylinder petrols that set off in 2nd in comfort mode.

italian job

Original Poster:

246 posts

231 months

Thursday 11th February 2016
quotequote all
Jobbo said:
I went from a BMW with ZF 6sp to a W204 C350 CDI with 7sp and currently have a BMW again with the ZF 8sp.

While at first the Merc felt like a step backwards from the BMW 6sp, I still have fond memories of it. It felt a bit like a 5sp with an extra 1st and an extra 5th gear for all the use 1st and 7th really were; but it was always possible to tell which gear you were in and (when using the paddles) whether you wanted to drop one or two gears fairly intuitively. Now with the ZF 8sp I struggle to work out whether I need to drop one, two, three, four or possibly five gears. 7 ratios, for me, seems to be the most I can sensibly distinguish without thinking about it.

The Merc also feels more like a traditional auto box in comparison to the ZF 8sp; the 8sp seems to lock up the torque converter at incredibly low rpm in an attempt to be more DSG-like. That's fine but I quite like the ability of a torque converter to increase the revs a bit almost instantly without changing gear.

I wouldn't have any problem swapping back to a Merc with the 7-sp now, even after living with the 8sp ZF for a while. Although that's me; if you are more of a PDK/DSG fan then perhaps you'd not feel the same.
Some really intresting observations thank you,if I can get another year out of my V70 I might be able to stretch to a 350cdi as apposed to a 320 or 280cdi....decisions,decisions.
Its great to ask a question and get so many replys.Cheers everyone.

Jobbo

12,972 posts

264 months

Thursday 11th February 2016
quotequote all
I'd rather have had the earlier C320 CDI than the Blueefficiency C350 CDI to be honest. I think you avoid the DPF on the C320 and it seems to be easier to tune. Worth checking out whether there's actually any difference between the E280 and E320 CDI engines beyond the ECU.

donkmeister

8,181 posts

100 months

Wednesday 17th February 2016
quotequote all
jamie w said:
My E320cdi always starts in first in C or S mode. I think I've read somewhere that it's only 6 & 8 cylinder petrols that set off in 2nd in comfort mode.
Ah, I've got a v8 petrol so that explains that - I would think diesels would need this feature more than a petrol engine though.

Also I spotted a typo in my post - in C/ W the REVERSE gear is a longer ratio (yes, the 7g box has TWO reverse gears!)

Sheepshanks

32,790 posts

119 months

Wednesday 17th February 2016
quotequote all
donkmeister said:
Ah, I've got a v8 petrol so that explains that - I would think diesels would need this feature more than a petrol engine though.

Also I spotted a typo in my post - in C/ W the REVERSE gear is a longer ratio (yes, the 7g box has TWO reverse gears!)
Even the old 5 speed has 2 reverse gears, and starts in the higher gear (2nd going forwards) in C mode. I don't think either box shifts gear in reverse though, although I've seen discussions on US forums where owners swear blind they've got up to like 40MPH in reverse and felt it shift!

Don't know if I was missing something, but I had a 7G+ equipped E Class courtesy car the other day which counted through the gears on the dash and I couldn't get that to start in anything other than 1st, even selecting gears manually. I only spent a few moments trying though.

Mr E

21,619 posts

259 months

Wednesday 17th February 2016
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My 500 definitely starts in 2nd if you're in comfort.
Why on earth does it need 2 reverse gears though?

Sheepshanks

32,790 posts

119 months

Wednesday 17th February 2016
quotequote all
Mr E said:
My 500 definitely starts in 2nd if you're in comfort.
Why on earth does it need 2 reverse gears though?
For slippy conditions - if I get one rear wheel of my 5 speed C270CDi on wet grass it'll spin it up from rest in S even if I'm ultra-careful. In C it doesn't do that.

Mr E

21,619 posts

259 months

Wednesday 17th February 2016
quotequote all
Sheepshanks said:
For slippy conditions - if I get one rear wheel of my 5 speed C270CDi on wet grass it'll spin it up from rest in S even if I'm ultra-careful. In C it doesn't do that.
Some form of "brake the spinning wheel" traction control would seem to be cheaper than an entire extra gear?

AC43

11,488 posts

208 months

Wednesday 17th February 2016
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I've had a 7g 500 for almost six years and really like it. As other have said, ultra-smooth, imperceptible changes.

Can't compare it to an 8 speed.

Sheepshanks

32,790 posts

119 months

Wednesday 17th February 2016
quotequote all
Mr E said:
Some form of "brake the spinning wheel" traction control would seem to be cheaper than an entire extra gear?
I suppose it has to slip a bit first for the traction control to work.

jamie w

175 posts

171 months

Wednesday 17th February 2016
quotequote all
donkmeister said:
jamie w said:
My E320cdi always starts in first in C or S mode. I think I've read somewhere that it's only 6 & 8 cylinder petrols that set off in 2nd in comfort mode.
Ah, I've got a v8 petrol so that explains that - I would think diesels would need this feature more than a petrol engine though.
)
I would have thought the diesel would benefit from it too. It's a niggle for me that it doesn't use 2nd (like the BMW 8spd does).

Slightly surprised little mention here of problems experienced with the 7g. The internet is not short of complaints about this box not being smooth changing.

Mine's pretty good but I do get the odd rogue jerky change and I've had the adaptation process run on it a couple of times by a good indie. It's also had 3 fluid changes (now on 115k).


hilly10

7,140 posts

228 months

Thursday 18th February 2016
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I have it in my E Class 220 and can only agree its great when wafting along returns great MPG on a motorway run. It does tend to hold onto the gears now and then. I never drive with it in Sport or manual not much point with only 177 bhp in a big car

AMGSee55

636 posts

102 months

Friday 19th February 2016
quotequote all
Fair point made re rougher changes. I have just swapped a c55 (5 speed) for an e350cdi (7 speed). Both of them when cold had jerky changes particularly across the first 3 ratios, the c55 being the worse of the two in this respect.
Conversely when warm, you hardly know what the boxes are doing - presumably this is just a Merc thing?? It was not a feature of my dad's '94 5-series as I recall or for that matter his old Citroen Xantia

Mr E

21,619 posts

259 months

Friday 19th February 2016
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Very rarely get a rough change, cold or hot.

KST80

243 posts

129 months

Saturday 20th February 2016
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AMGSee55 said:
Fair point made re rougher changes. I have just swapped a c55 (5 speed) for an e350cdi (7 speed). Both of them when cold had jerky changes particularly across the first 3 ratios, the c55 being the worse of the two in this respect.
Conversely when warm, you hardly know what the boxes are doing - presumably this is just a Merc thing?? It was not a feature of my dad's '94 5-series as I recall or for that matter his old Citroen Xantia
I have a 2012 E350 cdi, as said when cold it's not too smooth, it's got a service early March and I'm told a software update may sort this?
Other than that love the box.