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Discussion Starter #1 (Edited)
Hi guys, nice to meet you :).

2 days ago, finally, after 7 months, I received my A35 in Silver :). Generally very nice car and I like it.

The problem is that I noticed issue with gearbox and I hope you can help me.

This gearbox quite often tends to jerk on low speeds. I drive in Comfort. The problem is really strange when being on Manual mode. In Auto mode it also happens but it is not as bad.

Example 1: I am in Comfort mode (car is during break in) and Manual mode and I break to roundabout. Car reduces gears 4-3-2-1. In case of 3-2 or 2-1, often there is really noticeable jerk which feels like something is not good with the car. Also sometimes there are noticeable noises from gearbox when all this happens.

Example 2: When I put the throotle just after car goes down through 3-2 or 2-1, then there is lag for a moment, jerk/clunk, then my head hits the headrest and car goes.

Maybe I am too touchy because I think I treated the car a little bit too hard during first 30 kilometers (I wanted to properly arrange piston rings; engine oil was hot, but transmission had 50 C when I started to ocassionally put 50-75 % throotle on it but in range 3000 rpm - 4000 rpm) and now I connect those jerks with my fault, but please tell me how it is in your A35s.

Best regards
Mike
 

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Hi @Rester, congrats on your new car, and welcome to this forum.

If I'm understanding your symptoms correctly, the behaviour you describe is I believe inherent with double-clutch automatic gearboxes. They do in certain circumstances exhibit a clunk when engaging, usually in slow traffic. This type of clunk is less prevalent in torque convertor auto boxes. I'm not an expert so take my advice with a pinch of salt, but I suspect there is nothing wrong with your car, it's just a trait that you'll soon get used to and it will rarely bother you.

HTH
 

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Hi guys, nice to meet you :).

2 days ago, finally, after 7 months, I received my A35 in Silver :). Generally very nice car and I like it.

The problem is that I noticed issue with gearbox and I hope you can help me.

This gearbox quite often tends to jerk on low speeds. I drive in Comfort. The problem is really strange when being on Manual mode. In Auto mode it also happens but it is not as bad.

Example 1: I am in Comfort mode (car is during break in) and Manual mode and I break to roundabout. Car reduces gears 4-3-2-1. In case of 3-2 or 2-1, often there is really noticeable jerk which feels like something is not good with the car. Also sometimes there are noticeable noises from gearbox when all this happens.

Example 2: When I put the throotle just after car goes down through 3-2 or 2-1, then there is lag for a moment, jerk/clunk, then my head hits the headrest and car goes.

Maybe I am too touchy because I think I treated the car a little bit too hard during first 30 kilometers (I wanted to properly arrange piston rings; engine oil was hot, but transmission had 50 C when I started to ocassionally put 50-75 % throotle on it but in range 3000 rpm - 4000 rpm) and now I connect those jerks with my fault, but please tell me how it is in your A35s.

Best regards
Mike
I’m currently monitoring the FB page for the A35/45 where a couple of people have had gearboxes replaced already. Look at the A45s part of the site for the FB links.
 

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Discussion Starter #4
The general question is:
Is it possible that applying a peak torque (400 Nm) in range 3000-4000 rpm (interestingly, to achieve this, only need to use 60-75 % of accelerator pedal, not 100 %) can somehow destroy gearbox when car is during break in period?
 

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The general question is:
Is it possible that applying a peak torque (400 Nm) in range 3000-4000 rpm (interestingly, to achieve this, only need to use 60-75 % of accelerator pedal, not 100 %) can somehow destroy gearbox when car is during break in period?
No. It should accept the peak torque of the stock car without any problem. If the gearbox stops working it’s because it is defective and MB will need to change it free.
 

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Discussion Starter #7 (Edited)
Thank you. I asked because on sticker on windshield, there is written "avoid full load". It is a little bit enigmatic because it can be about:
  • full torque
    (full load of peak torque 400 Nm)
  • full throotle
    (I don't know why it would matter if peak torque you can reach using just 60 % of throotle, especially when car is in Comfort and transmission in D - pushing more than 60 % of throotle will not add any more load because it actually acts with max force [max torque] on 60 % of throotle)
  • full weight on car
    (5 passengers, many suitcases)
 

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This is only for the running in period. So after 1,000 miles we should be okay to let rip.

I think the running in period is important for the higher performance AMGs and I certainly religiously adhered to the 4,500 rpm.
 

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Discussion Starter #9
Yes, since the beginning of this topic it is all about a new car which is during run in period :). Do you guys have any idea what could mean "avoid full load" in case of run in period?
 

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Honestly, reading this, I come to two conclusions. If you were going to be so worried about the sensitivities or bedding the engine in, why didn't you just take it easy as it asks on the sticker? Secondly, if it's a new car and you're worried about how its working then get it chucked back into Merc and ask them to report back to you. You have new car warranty for a reason, so any sticky issues at the start can easily be dealt with.
From my insight into running one for a year now - the gearbox is a bit clunky and sometimes a little frustrating, so what I'm reading doesn't exactly surprise me. I have been lucky enough to run an S4 and now A35 as my last two cars. Both brand new (lease) and tbh I pushed them from early on and have had no issues. It doesn't mean that's a hard and fast rule, but your 'behaviour' sounds pretty light to me so shouldn't overly worry you about what you may or may not have done to the drivetrain. Good luck!
 

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Discussion Starter #11
The reason is I was too much focused on good sealing of piston rings for the first 20 miles and in some sense I forgot to keep an eye on gearbox and others. It's past now. Hope it will be well. Thanks.
 

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I've had three cars with dual clutch gearboxes and they all display this characteristic to some extent. I believe its nigh on impossible to be rid of it. However, I only experience this behaviour in comfort mode. You can adjust your driving style to somewhat negate this happening though. Its hard to explain, but you want to keep on the power progressively, so the box isn't hunting for gears. A little pressure will help make its mind up.

After waiting for the oil temp to reach 80c, I always drive in Sport+ mode. The pops and bangs are too addictive and the throttle is more instant.
 
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