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jerk between 10 and 20 km/h, This is not gear shifting
Hi,
I feel a jerk when the car starts moving at a speed between 10 and 20 km/h. This is not gear shifting. This also happens when the gearbox is in manual mode in one gear. I tried starting from first and second gear, everything is the same.
The problem appeared after I tried to do computer diagnostics myself with Xenry. It was my first experience.
I only wanted to check the gearbox adaptation data when shifting gears. Because before there were sometimes jolts when switching from third to fourth gear.
Maybe someone has some ideas what could be the reasons for this malfunction?
Do you mean a thud when coasting at like 10, and you then accelerate? Or a thud when shifting from reverse to drive? Or a slop in the drivetrain? That would likely be a bad front driveshaft Ujoint . If that is it, stay off the highway , confirm it’s the u joint and fix it.
Hi,
I feel a jerk when the car starts moving at a speed between 10 and 20 km/h. This is not gear shifting. This also happens when the gearbox is in manual mode in one gear. I tried starting from first and second gear, everything is the same.
The problem appeared after I tried to do computer diagnostics myself with Xenry. It was my first experience.
I only wanted to check the gearbox adaptation data when shifting gears. Because before there were sometimes jolts when switching from third to fourth gear.
Maybe someone has some ideas what could be the reasons for this malfunction?
Check the u-joints between the front differential and the transfer case for play. A failure can cayse extensive damage. Check all front and rear drive-line components for play and condition. Also check engine mounts and transmission mount.
If all those components are competent, then perform a new transmission adaptation and run the transmission in through the relearn procedure as if it were rebuilt. If the 158k+ is miles not km, the transmission may be at the limit of what it can adapt to.
Erase all existing transmission trouble codes because codes acquired during relearn may be invalid.
Do you mean a thud when coasting at like 10, and you then accelerate? Or a thud when shifting from reverse to drive? Or a slop in the drivetrain? That would likely be a bad front driveshaft Ujoint . If that is it, stay off the highway , confirm it’s the u joint and fix it.
No, all your assumptions are wrong.
It looks like a short-term shutdown of the engine.
I can see the tachometer jerking downwards during the jerk.
No, all your assumptions are wrong.
It looks like a short-term shutdown of the engine.
I can see the tachometer jerking downwards during the jerk.
That’s important information. Try not to keep us guessing.
At less than 160,000 km the transmission is probably mechanically good even if it hasn’t been maintained per recommendation. Do an engine and a transmission diagnostic scan and report any trouble codes.
The engine and the transmission interact at shift points. There may be trouble there.
Thank you for your answers, but I still haven't solved the problem.
My car is in the official Mercedes service for the 3rd day, but they haven't solved the problem yet. As far as I know, they reset the adaptation and re-adapted the gearbox. This didn't help, they updated the firmware of the TCU but this didn't help either, they asked for help from the head office.
Maybe some of you will have some ideas?
I will supplement and clarify the description of the problem:
I have a problem with the car jerking between 10 and 20 km/h and it the most likely is not related to gear shifting.
For example - I put the gearbox in manual mode and start driving in 1st or 2nd gear at the moment when the speed increases from 10 to 20 km / h (most often 13-14 km/h) the car jerks. And, maybe it matters, the next moment I hear the door locks locking. It looks like the clutch suddenly off and on again.
The problem appeared after I tried to do computer diagnostics myself with cheap replica of the Tactrix Openport interface and Xenry. It was my first experience. I noticed sometimes not smooth shifting and I only wanted to check the gearbox adaptation data when shifting gears.
I didn't know where to look for them and found them in the Author data menu.
In the screenshot I have indicated the sequence of actions
I got a list of adaptation values there but they were outside the limits.
I don't even know what it was.
Later I found the right place in the menu to view the adaptation data, and everything was within the required limits.
I think at that moment something broke and I see nonsense.Later I found the right place in the menu to view the adaptation data, and everything was within the required limits.
As I remember now, I never gave any commands to reset or change values. However, the next day the machine started jerking.
If it is the clutch or whatever it is called that is triggered, then it probably receives a command from the Transmit Control Unit and some parameter has an incorrect value. The service updated the firmware, but the parameters values probably remained the same and the problem remained.
How to reset all settings to factory settings including developer settings?
What do you think about the idea of trying to replace the TСU with another used TСU? How expensive and difficult can this be?
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