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anyone experience this.. like a hard thud on downshifts, especially 2nd to 1st when going slow.


dealer wont acknowledge it even exists.. saying "they are all like that" but my 453 was never like this when new.
 

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anyone experience this.. like a hard thud on downshifts, especially 2nd to 1st when going slow.


dealer wont acknowledge it even exists.. saying "they are all like that" but my 453 was never like this when new.
I don't buy it either. 2-1 downshifts usually aren't smooth in any manual-based transmission.
 

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Yes, when the AC is on the downshifts into second as well as first gear can be clunky. Much smoother without AC. I started noticing this on my 453 after about 5 K miles. It will be addressed at my 10K service. I'm wondering if it's a software issue.
 

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anyone experience this.. like a hard thud on downshifts, especially 2nd to 1st when going slow.


dealer wont acknowledge it even exists.. saying "they are all like that" but my 453 was never like this when new.
Hey @rijowysock, how many miles are on your car? The DCT does go through a learning process for shifting around the driver's driving style. Dual-clutch transmissions also shift a bit differently than traditional automatics.

If you still have concerns that you feel your dealer isn't addressing, feel free to contact our corporate customer assistance hotline at 1-800-367-6372.
 

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anyone experience this.. like a hard thud on downshifts, especially 2nd to 1st when going slow.


dealer wont acknowledge it even exists.. saying "they are all like that" but my 453 was never like this when new.
Mine and my wife's both exhibit this hard downshift behavior. It tends to be more noticeable when slowing down quickly and braking firmly then when I'm basically coasting to a stop. I mentioned it at my 10,000 mile check-up and I don't believe it was addressed. I'm also not certain if any software updates were done during the service call. Since it was short in duration, I tend to think nothing was altered.
 

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Prior to taking my 453 in for recent service at my local M-B dealership, I too was experiencing increasingly rough gear changes between 1 and 2. I purchased a bottle of Marvel Mystery Oil from a local auto supplier and tried that first. I found that it dramatically improved the car's overall performance but it didn't offer a solution for the 1-2 / 2-1 gear change issue. After getting the car back from service (still battling fuel tank issues), the service guys performed a hard reset on the car. I hoped that this would allow the car's computer to re-train itself. The car now shifts smoothly between gears 1 and 2.
 

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A 2-1 downshift is there because a skilled driver will know what the trans is doing at all times and takes advantage of it for acceleration purposes. The car is programmed to give you access to 2-1 instead of 2-N, under many scenarios. And now engine braking is larger part of the new programming.

2-N is what the smart 451 had a tendency to do, and that's what caused some people to complain about the 451 having too many shifts for their tastes. It's because it would jump to 2-N, and heavy throttle would jolt you from 2-N, N-1, 1-2, instead of the 453 choosing 2-1, 1-2 if acceleration is needed. Otherwise you're coasting to a stop and it's irrelevant. You get sportier programming with the 453 thanks to the dual clutch's ability to shift through all gears much more quickly than a single clutch.

Some folks won't know what the heck I'm talking about, some will. I hope it is a useful explanation nonetheless. :nerd:
 

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I've found that the automatic transmission has allowed people to be dolts regarding this.
I neglected to expand on this thought. If the smart 451 is coasting at slow speeds, it can choose 2-N, and climbing out of N is where smart car transmission critics will lose their minds. Strong pressure typically turns 2-N-1-2 (causing "hesitation" or "jerking" according to critics) and very gentle steady pressure typically turns 2-N-2 and a skilled driver will be patient enough to crawl out of the hole in 2 for a smooth acceleration. A smart car transmission hater (bad technique) will lose patience and eventually apply strong pressure (but too late) causing a 2-N-2-1-2 shift pattern and then turn around and blame the car for "jerking." Yes, I know other vehicles may not need technique. I get it. But they also are large engined cars, usually 1.8L's or larger, and don't come equipped with automated manual transmissions.

I've never tried explaining this before, it is difficult to explain. Some folks will get it, some won't. It's a 3 cylinder engine with 1.0L. Technique is necessary to achieve results.

With the added power and dual-clutch of the smart 453, less technique is necessary to achieve results. Technique is still necessary though for best results.
 

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I've never tried explaining this before, it is difficult to explain. Some folks will get it, some won't. It's a 3 cylinder engine with 1.0L. Technique is necessary to achieve results.
Most people are more about something working for them rather than vice versa. I tried explaining many times that if you drive the 451 it is fun. But most people don't want to drive a car they want to be driven by it.
 

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But I love the BRABUS programming though! It sticks with high rpms so you can complete your maneuver, complete your turn, then resume accelerating out of it already at high rpms.

YES. You can take your foot clear and complete off the throttle, and the auto-manual trans will stay in gear keeping your rpms high until you resume your previous foot action on the accelerator pedal. Be careful with the BRABUS. Don't apply way too much pressure or you just might engage a downshift to get the rpms even higher due to the lower gear. Apply a touch of pressure and slowly increase it will NOT backing off until it shifts up. It's definitely a more aggressive program.

Normal program: Accelerate up to speed, get the rpms up to say 4,500. Remove your foot clear off the throttle. Program shifts to next higher gear expecting you to resume your acceleration (less aggressively) by placing your foot back on the throttle.
BRABUS program: Accelerate up to speed, get the rpms up to say 4,500. Remove your foot clear off the throttle. Program stays in same gear expecting you to want those higher rpms when you resume your acceleration by placing your foot back on the throttle. Carry it up to nearly redline before it finally shifts to the next higher gear.

There are all sorts of various programming differences between the two models. I just offered one cookie though. :nerd:
 

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Great explanation of the 451 Brabus shifting program. I thought I had read several years ago about the Brabus having about 20% faster and more aggressive shifting than the Passion/Pure models. Your excellent description confirms this for me. :)
 
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