will the 2015 S550 4Matic sedan have a 9-speed or 7-speed tranny?








Last edited by cookstar; Feb 16, 2014 at 09:55 AM.
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Agree for 100%
7G-Tronic should be replaced asap as it is no longer up-to-date compared to any peers which typically use the ZF transmission.
M
M
With the torque curve that the S550 has and the low RPMs while cruising I don't see how having more gears will increase fuel economy. Under normal acceleration I rarely go over 2400 RPM.
I assume, that like you said, MB could make the existing transmission shift faster or smoother if they wanted, trying to understand how more gears will help that. Until they make faster gear changes the only thing that I see happening with more gears is spending less time applying torque and more time sliding from one gear to another.
If we really want a smooth acceleration with no time spent shifting than we should be asking for the next generation CVT, but I understand there are challenges with high torque applications and also a perception in the market that they are inferior and people like to feel shifts so the current CVTs are programmed to purposely have "rough" spots to simulate shifting.
I am just concerned that the number of gears at this point is becoming a meaningless marketing item - "if having gears is good, than having more is always better" I don't think is a correct assumption.
With the torque curve that the S550 has and the low RPMs while cruising I don't see how having more gears will increase fuel economy. Under normal acceleration I rarely go over 2400 RPM.
I assume, that like you said, MB could make the existing transmission shift faster or smoother if they wanted, trying to understand how more gears will help that. Until they make faster gear changes the only thing that I see happening with more gears is spending less time applying torque and more time sliding from one gear to another.
If we really want a smooth acceleration with no time spent shifting than we should be asking for the next generation CVT, but I understand there are challenges with high torque applications and also a perception in the market that they are inferior and people like to feel shifts so the current CVTs are programmed to purposely have "rough" spots to simulate shifting.
I am just concerned that the number of gears at this point is becoming a meaningless marketing item - "if having gears is good, than having more is always better" I don't think is a correct assumption.
Not more gears, but a new transmission, new hardware, new software. More gears will give you better fuel economy especially on the highway. CVTs don't belong in luxury cars. I'm sure Mercedes could make the 7G shift as smoothly and quickly as the ZF 8HP, but they haven't. Yeah 9 years is a getting into a marketing driven thing, but they said the same thing about 6 speeds back in 2002 and then 7 back in 2004.
M





Last edited by syswei; Feb 18, 2014 at 07:20 AM.

If the 9G-Tronic will have similar initial issues as the 5-speed and the 7-speed transmission had (I don't know how well the 4-speed did initially), I'd rather take the marginal loss from 7 gears.
Resale value could be significant, depends on how reliable and smooth the 9-speed tranny turns out to be.



Interesting read. The jeep went from 19 mpg to 31 mpg with the 9 speed it just got.
I also read that the new S with 9 speed will do 75 mph at 1,350 rpm. That is low!


