Solved transmission issue - Too good to be true!

5five

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So here is the story...

My 7 speed Mercedes used to have rough shifts (1-2 and 3-2) only when cold.

From "cold", I mean when the transmission is cooled down like first start in the morning. I do not mean freezing temperature.

I was away for 2 months and my dad drove the car meanwhile. He is a slow driver and I am not.

When I came back after two months, I noticed that the car STOPPED having rough shifts when cold. I was so glad that the problem solved by itself!

But I was wrong..... After 3 days driving the car, the problem started again.

I believe that this is because the transmission has adapted to the way I drive. Like I said I am a fast driver but my father is not. So, maybe the transmission fails to adapt properly to fast driving?

I don't believe that there is a mechanical failure. The very rough shifts would not have stopped although my dad was driving if there was really a mechanical failure.

I would appreciate to know what can be done to solve this issue.

Thanks:thumb:
 

mirras

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Drive like your dad.

Seriously though, I believe the gearbox can have adaptations reset, I had this done on my W221 with 7 speed box and it has not been jerky since. I suspect I may drive more like your dad than you though....
 

Giantvanman

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I am not entirely convinced a reset is the solution.
The gearbox was rough-changing when you drove it. This became smooth after your father used it for two months. You have the car back and after a couple of days, the gear changes are back to the way they were. Exactly what are you doing differently from your father? Are you, for example, expecting optimum performance from the second you turn on without any gentle driving warm up period?

A Google search on 'reset mercedes automatic gearbox' reveals lots of hits including YouTube clips but I seriously doubt this is the issue or solution.
 
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5five

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I am not entirely convinced a reset is the solution.
The gearbox was rough-changing when you drove it. This became smooth after your father used it for two months. You have the car back and after a couple of days, the gear changes are back to the way they were. Exactly what are you doing differently from your father? Are you, for example, expecting optimum performance from the second you turn on without any gentle driving warm up period?

A Google search on 'reset mercedes automatic gearbox' reveals lots of hits including YouTube clips but I seriously doubt this is the issue or solution.
When I drive the car first thing in the morning, I give the car enough time to warm up.

Although I drive fast sometimes, I am always gentle with the car. I NEVER make big accelerations with 1st gear or 2nd gear. I also never rev the car to the limiter. I rev the car to 4000 RPM maximum.

But when I drive, I guess that I make the transmission work more than when my dad drives. I make frequent gear changes.
 

SLKNick

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"Adaptive Learning" works both ways ....
 

MBScoob

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My car was driving lovely and smooth, with silky gear changes. It was in the dealer having some bits looked at and, when I drove it home it was like a different car for the first few miles. It was holding on to gears longer - despite me pottering in traffic - it was jerky and so not smooth changing gear. It all settled down after a while, but I do wonder exactly what they did! I was close to turning around and heading back to the dealer at one point, but it did settle down. It's like this pretty much every time it's been into the dealer for a service or other things.

For the record I generally potter, but do get my toe down every so often. Car definitely does learn your driving though. I.e. If I've been driving the car a bit harder for a couple of days, then do a certain run at a steady potter, my mpg is just "ok". If I then potter for a few days and to the same long run, mpg is markedly improved. Same is true if I drive hard after pottering for an extended period, car does not seem to respond as well.

Personally, I think the car should just respond based on throttle input and not try to learn a driving style that changes on a whim.

Scoob.
 

whitenemesis

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Or there should be a simply 'on dash' reset button to clear the memory?
 

Rory

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- it was jerky and so not smooth changing gear.
..but OP descripes the changes as "very rough". It's hard to imagine changes that would truely meet that description.
 

MBScoob

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..but OP descripes the changes as "very rough". It's hard to imagine changes that would truely meet that description.
True, it's all relative though. My idea of "not so smooth" might be someone elses idea of "very rough". Same as I love the firm suspension on my Merc, but it's sublimely soft compared to my Impreza, though many consider the Merc overly firm when running on 18's.

Very interesting if it is just the car (over?) reacting to different driving styles though. It'd be fascinating to know exactly what logic the car is following when it "learns" a driver, so to speak.

As an aside, while I only do longer trips of 20 miles or so, a lot of that however is slower roads and towns / villages. As a result of that, and my tendency to potter, my car delivers it's best mpg when pottering around town, it's not so good at steady 70mph runs. I'm guessing this is my car learning to so degree. My friend, conversely, with the exact same engine and gearbox, though in a Coupe not an estate, see's the opposite, he generally does more motorway driving.

Scoob.
 
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5five

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When I say "very rough", I mean its like a car hit my car at the back :eek:
 

renault12ts

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Try this tomorrow morning, instead of being gentle first thing when the box is cold, don't be...drive it smartly, I think you'll find the 1-2 is not rough.

If I am gentle first thing, that very first 1-2 will be as you have just described.
 

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