E450 Wagon transmission hesitation in traffic
 

I have a few days old 2019 E450 Wagon and have noticed a strange behavior when sitting in stop and go traffic.

For some background, the car is in "Comfort" mode as suggested by the manual during the first 1000 miles break-in of ownership.

To specify the problem, when I am driving in traffic and idling along in second gear (as indicated on the dash), the car appears to hesitate and then surge when I lightly press the throttle to keep with traffic. I estimate going less than 15-20 mph. This problem also exists in "Economy" mode. However, I do not notice this behavior when driving at speed. I also have not changed to "Sport" mode to determine if it persists because of the break-in recommendations.

Has anyone else noticed this with an E400 or E450? In a search on this forum, one other user indicated that the adaptive transmission needs to train itself and all works itself in the end. Can anyone corroborate this?

Otherwise, the car has been lovely. Beautiful design, handling and technology. It's a delightful and worthy upgrade from my prior 2015 E350 Wagon.

Cheers.

I have an E400 and if I had to guess, it sounds like because in Comfort you are in 2nd gear, the car is not as responsive and then the turbos spool and you get a bit of a rush in acceleration. I also had a 2015 E350, and those engines were naturally aspirated giving a more linear power approach. In and around town I use Sport mode as it makes a world of difference for me in traffic situations. I think once broken in you'll find this to be the case as well.

Based in what you said, I tried to keep the accelerator smoother and the transmission did seem smoother this evening in traffic. Perhaps I'm too used to being lazy because of the old E350. With only 250 miles in the car, I'll reserve judgment for another 1k and then report back if things improve, or they don't. Thanks for the response.

I've been "getting used to" my E400 for over 3 years now. This power train has to be one of the most difficult to drive smoothly that I have ever encountered. Mine is fine if you drive very gingerly, like an elderly lady. It is also fine if you put it in Sport mode and pound on it. Everything else in between and it is almost impossible to pull away from a stop smoothly. I've only in the last year or so been able to learn the best way to modulate the throttle to drive away without any surging, bogging or roaring up on the car in front.

I have had the car to the dealer several times for this (along with the dreaded "dead spot" where you let off the throttle to slow down, then stop on the gas, and. . . nothing). There has been nothing they can do except reset the computer control units, which only lasts a few days, and then we're back where we started from.

The car can be driven smoothly. It just is not easy.

Do you think that it's as a result of the turbos, ot just the transmission itself?

I do not have any issues driving smoothly. I use individual mode with the engine set to sport and the other settings in comfort. Then I drive in a normal fashion - neither aggressive nor sedate. The main effect of sport mode is to improve throttle response. The rpm is the same as in comfort mode for a given speed so there is no fuel economy penalty.

The 7G transmission that SteveE400 has and that I have had in two cars previously is temperamental. More so for some than others. The new 9G, perhaps by virtue of having two more gears does not languish in any one gear the same as the 7G did. nycebo, looking forward to your report once broken in.

And that 9G might be the only reason I can find to move to a 2018 from my 2015. Not at all sure I would go to E450, as I almost never buy "first year" model cars. I'll let the other early adopters do the de-bugging first.

The 9G is an improvement. The 2019 E450's use the same engine as the 2018 E400's and your car - M276 DELA. They are tuned up a bit. Essentially it's a 3rd model year, and as you know the powertrain has been in use for some time now.

Okay, 400 hundred miles in, I can better specify what I'm detecting in stop and go traffic:

It's not the transmission changing gears; rather, it's the same gear (in this case 2nd gear in either E or C mode) roughly engaging when I very lightly touch the accelerator pedal to start moving again. It's clunky and not smooth. It's more of an ON and OFF feel, rather than a smooth power transfer and engagement.

However, once moving, the shifts return to their prior smooth and efficient transitions that one expects from the E class.

As usual, I'll report back as I near 1000 miles and higher.

Silly question: Its not the auto stop/start engaging? My 2018 E400 is very smooth from a gentle standing start in traffic, but there is a jerk when auto stop/start is on (I usually deactivate it). If what you are describing continues, I don't think it normal.

Thanks for the suggestion. I wish it were! However, I always disable stop/start when I'm in traffic. No, it's the neutral into gear engagement that is chunky. It's not massive, instead it's just jerky.

On an aside, I only use ECO stop/start when I know that I'll only be stopped at lights and not in a long, never-ending line, that seems to get longer every year! :nix: