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Hi,
I have 2015 gla45 and sometimes right after you fully stopped it make low deep sounding knock, and it feels like you got tapped from behind very slightly.
After dropping car of at the dealer 2 times ,dealer said that is normal with sport transmition in 45amg we have.
the dealer communicated with Germany amg engineers about it, i called mb service directly, and they said yes its true, its shows in their date.
i think its total bull ****.
Any ideas?
also, when i put in reverse it make metal to metal shift sound. also they said its normal.
c
 

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I get the same in my 2016 GLA45. At first, I thought it was something bumping around in my trunk (maybe underneath where the fix-a-flat kit was). I guess this is what it is?

Not a huge deal-breaker, but I have had friends mention it when riding in my car, and I just tell them I have stuff in the back (which I though it was). If it ends up causing more problems like abnormal wear and tear, then I'd be more concerned.
 

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nothing new https://www.youtube.com/watch?v=izIsIJKPYd4

A lot of A-class are complaining about it, it got quieter i believe in 16+, mine is a 16 and does it once in a while, a combination of selecting fwd/rev with hold function active or not.

MB took a few transmission apart for some A45s to diagnose the problem and determine it to be "normal" for now. Some say a transmission software upgrade will reduce the noise but who knows...
 

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Oh, and I also get similar metal knocking when I put it in reverse (nothing too loud or startling), but I also hear something similar in my Audi Q5, so I was just guessing it uses similar mechanics when shifting. Is it a German thing?
 

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Woah... my 16 GLA45 is nothing like that. That sounded like grinding. I'd probably be more concerned if I heard that. Mine sounds like I have something in the back that hit the seats when coming to a stop.
Think that "hit to the seat" feeling is when the transmission is going from 2nd to 1st when coming to a stop, can be jolting in "S+" and "R" modes, less pronounced in "C". The car is a little aggressive getting ready for you to gas it and take off again.

On the other hand, a lot of people in previous yrs (A/CLA/GLA) complaint about the car "lagging" when coming to a stop and going again (think metering lights to a highway) because the car would stay in 2nd gear longer and not go down to 1st. So you cant have it both ways with mercedes i guess :|
 

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Discussion Starter · #8 ·
Guys, something is up.
We all dig the car here obviously.
But its not normal, but whatever.
The love is blind :)

check out my oz wheels. i put photos them in my profile area, dont know how to navigate here.
 

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Hi,
I have 2015 gla45 and sometimes right after you fully stopped it make low deep sounding knock, and it feels like you got tapped from behind very slightly.
After dropping car of at the dealer 2 times ,dealer said that is normal with sport transmition in 45amg we have.
the dealer communicated with Germany amg engineers about it, i called mb service directly, and they said yes its true, its shows in their date.
i think its total bull ****.
Any ideas?
also, when i put in reverse it make metal to metal shift sound. also they said its normal.
c
Hey, i got the same problem too. its like a big grind right under your seat. i find out only happens when ur slowing down to a stop(such as approaching red light), and the car is downshifting from 2nd to 1st (eco/sport), when i downshift from manual from 2nd to 1st myself, i dont hear the sound, but i do get some bounce from power. i went to dealer, they realize its an issue but so far they got no way to solve it they said..wtf?
 

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M-type, caug, has anyone tested whether it's more pronounced in S+/R? That seems reasonable that it's a very late downshift. Possibly the transmission is holding in power band, then the ECU realizes you're actually stopping vs deep slow for corner and gives up and downshifts. Michael might be on to something. It sounds like a programming issue - the shift is too hard for the uses, but if m-type is correct, then it's a correction for a shift that was once too soft.
 

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Discussion Starter · #11 ·
Mine does it in Eco mode mostly since i am driving 70% in C.
yes its only heppeing in low gears 2-1 or when driving slow around parking lot trying to find spot to park.
but it happens in all modes as well.

C
 

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Mine does it in Eco mode mostly since i am driving 70% in C.
yes its only heppeing in low gears 2-1 or when driving slow around parking lot trying to find spot to park.
but it happens in all modes as well.

C
ill have to retest my manual mode again then, because if it let downshift rev matching do the job, theoretically, its suppose to grind like in other modes. btw caug, how u have that footnote of your vehicle stat when u post something lol. im just new to forum.
 

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Sorry been away on holiday, mine does not jolt in Comfort or Sport from 2->1. Mine is 2016, Caug is 2015 i believe, any 2017 want to chime in?

Like most people, you slow ease on the brakes as it come to a stop and the car gets confused and shift "hard" into 1st.
 

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I have a April build 2015 GLA45 and it does not have any of the shifting characteristics that is being described. Odd....
 

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I've been using the AMG menu to track the shifts, and I actually believe it's the 3-2 at slow speeds. It's very subtle if you're not looking for it - the suspension gives me larger jolts merely stepping off the quarter-curbs common on driveways in my neck of Europe. I have yet to drive my car outside of C.

That being said, though I'm more able to reliably notice it now, it doesn't bother me like it does caug.
 

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Woah... my 16 GLA45 is nothing like that. That sounded like grinding. I'd probably be more concerned if I heard that. Mine sounds like I have something in the back that hit the seats when coming to a stop.
Ditto that - nothing like that here or the jolt from 3-2 downshift . . . in any mode - 2016 here as well. Oct 2015 Manuf. date.

I'll keep an eye/ear open for this.
 

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That youtube playlist is pretty good. This is the A45 4-matic from 2013:


Pretty good video on how our drivetrains work - except - 90% sure our GLAs are max 50/50 torque split front/rear . . . I've dug and dug and dug and can't find more details on exactly what the Dynamics package does to that (Race mode, LSD). Would love to find it.
 

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Sorry been away on holiday, mine does not jolt in Comfort or Sport from 2->1. Mine is 2016, Caug is 2015 i believe, any 2017 want to chime in?

Like most people, you slow ease on the brakes as it come to a stop and the car gets confused and shift "hard" into 1st.
its not the shifting issue.. it shifts fine but along with the shift theres a huge grind right before u approach a stabilised stop.
 
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