BC MB

I just returned from an extended test drive of two C43 sedans. Both were almost new and both suffered from the same issue. When up-shifting in Sport+ or Manual modes at between 4000 an 5500 rpm at quick acceleration, the transmission makes an annoying boom sound and slips. It feels like a down shift as the car feels like its braking/stuttering for a split second before engaging the next gear. Appears to occur in all gears.

Has anyone else experienced this? Is it normal for the 9 speed or is this an issue that resolves itself as the transmission gets worked in?

I also drove the C63 and the 7 speed shifted as smooth as butter. If it happened with only one C43 then I would have thought it to be a defective vehicle but it happened consistently in two vehicles. The salesman came with me on my request and confirmed the issue. He wasn't sure if it was normal or not either but definitely agreed it was not acceptable.

5ilver-5urfer

Are you talking about the horrendously loud bang sound that you hear from the exhaust when you shift up at 4000+ RPM in Sport/Sport+ mode? If so, I paid extra for that.

ultran00b

Pretty sure that's the intended effect AMG wanted when in the Sport+ mode. The 9G transmission is buttery smooth in Comfort and Eco.

Try driving a E92 M3 or the new F80 M3/4 and set the shifts to be the harshest, and you will notice the same effect. 991s with the PDK and Sport Plus also have the same feel (albeit much more violent in their upshifts).

BC MB

Wow. that's a deal breaker for me. Not only is it extremely unpleasant, IMO, but it can't be good for the transmission. Its not just a horrendously loud bang, as eloquently and accurately described by 5ilver-5urfer but it also seems to cause the car to stutter for a split second which led me to believe the transmission is slipping.

ultran00b, not sure about the 911 but I have a 2013 Boxster S with PDK and I have no similar issues. The PDK on the Porsche is extremely fast and sounds amazing with the optional sport exhaust. The 2017 C63 does not suffer from this issue either. I can't believe AMG intentionally designed it this way. I cringed every time I heard it as I expected the transmission to be sitting on the road.

Its a real shame because I liked everything else about the car. It handled well, feeling slightly more agile than the C63 and the steering and braking were well executed.

BC MB

UPDATE:

I test drove another C43 today at a different dealership and to my surprise the issue was much less obvious. There was still a bang but it was tolerable and the car did not stutter like the other e43s did. I wonder if the demos from the other dealership were abused.

Astolfo

You need an adaptation... drive the crap of your car BEFORE you buy it and ask the dealer to fix it before you put your $ down.
It can be improved... my dealer got my 2016 E63s shifting almost as good as my PDK, which after the F1 is the best gear/transmission I have owned.
But then do not forget that allegedly you bought a car for the track...and not to drink a Martini, stirred..not shaken....

Sanch

My car bangs all the time in sports +

Not sure if its the same kind of bang you're referring too.

BC MB

The bang only occurred when upshifting and on the first two vehicles the bang sounded like a blown transmission and caused the car to stutter. On the vehicle I drove today the bang was more like a mild backfire with no noticeable stutter.

Sanch

The bang should be a back fire.... not to sure about this stuttering.

Doesn't seem normal.

1Gunner

Curious people who buy an edgy sports car only to complain or comment about charming abeit inherent rough edges.

I'm sure MB also builds buttery smooth people transporters.

Seanhfx

I can't imagine both cars sounding like a blown tranny. I test drove C43 2 weeks back and loved the sound it made in S+ when up/down shifting. When driving normally, it was like a totally different car.

Did the last car you tested have the AMG Perf exhaust?

Astolfo

I know it sounds bad but this is MB's own making. Most people do not know what they are really buying.
This is why for some it would be better to have a "tune" and then an AMG.
Similar to the S line and R/RS in Audi.
You want the flicks and a little more power/torque get the S Line, you want a "track" car then get the RS-R.
But AMG has become so commoditized that anyone can buy it. Hell there are AMG's worth 120k+ siting outside for months if not a year like my 2016 wagon. Just plain travesty...and sad.

AV1

Stuttering and/or braking effect when upshifting is definitely not normal !

Does it also stutter when coming to a hard full stop from high speed ?

If so that particular trans is not healthy - I'd get the dealer techs to check the valve body/conductor plates etc. these are very common continuing faults with all MB transmissions.

As you have noted not all the vehicles you test drove have the same symptoms, don't worry too much about it - if it happens on the vehicle you end up purchasing the warranty will take care of it

coladin

Calling the C43 a sports car is quite the stretch, but I see your point.

Astolfo

I could not disagree more, get it fixed before you buy the car. if not you could end up wasting your time trying to get the tech adapting the gear box.


The idea of buying something worth this much money to have to fix after buying is just not comprehensible and wired.


Unless your time is not worth a dime get another salesman and get the master mechanic on the car with you, reproduce the issue and resolve it before you pay.

BC MB

Perhaps you should reread my initial posts more carefully. If you did you would note that I drove the C63 during the same visit to the dealership and found its exhaust note to be brilliant. I would consider that car to be a significantly more "edgy sports car" than the C43. You would also have noted that I own a 2013 Boxster S which has the Porsche sports exhaust, which exhaust note is also brilliant. What I experienced was not edgy but, as 5ilver 5urfer put it, horrendously loud and jerky. There is edgy and there is defective and these cars clearly fell in the latter camp. As these were demos I wonder f they were abused and/or maybe early production cars.

I am not trying to insult your car and would appreciate not being insulted because you are offended. In fact other than that one issue, I really liked the car.

1Gunner

Not trying to insult you or your automotive diagnostic perceptions. Sorry if you took it personally. You may well be 100% correct.

The C43 while not exactly a "sports car" it is a car with an edgy appeal over say the C300. It's what swayed us when replacing my wife's Lexus F-Sport GS350. Guess I should have been clearer.

Again sorry to ruffle your feathers.

alexasa

iTrader: (1)

You need to get the transmission up to temperature.

How long were the test drives? Usually it takes about 3-5 minutes in ~70 degree weather to get the transmission up to speed.

BC MB

No problem 1 gunner. FYI, I received a call from the dealership this morning and apparently they had their tech look at the cars and noted the problem and described it as a "loud clang accompanied by a slip and jerk". They are trying to determine the cause. I hope this is an isolated incident.

Alexasa,

I drove the first one for about 25 mins. and I took the salesman with me in the second one for about 10 mins. It was a cold day. The dealership is arranging an extended test drive in a third vehicle speced the way I want it as I really do like the car. Hopefully the three times a charm.

Thanks for your suggestion This time I will make sure the oil temp is above 80 and see what happens.

PeterUbers

Exhaust pops are normal and desired in an amg... perhaps don't buy an amg if you don't like it;

https://www.youtube.com/shared?ci=-vNnND8ywlo

(copy and paste)


also...


https://mbworld.org/forums/c43-amg-c...ml#post6982241

a video of f1 car shifting and popping

https://www.youtube.com/shared?ci=4q8iFCBk7og

AV1

That above depends on how one has or is purchasing the car and would apply to people buying vehicles off the dealer floor...I do see what your trying to say, personally I wouldn't buy it if something was wrong I'd look at and consider another as the OP is doing

However if it's a brand new factory delivered order and the car has these or other problems you then have to exercise the warranty which is more the point I was trying to make.

I had the exact same problem/symptoms described by the OP right from day one after taking a factory ordered delivery of mine, complained about it and sure enough resulted in the valve body, electronic module associated with it and conductor plates replaced through warranty with no issues from MB and thankfully it's still all good

It seems some people commenting on this thread are getting pops and bangs and whatever else from the engine/exhaust confused with what is a transmission malfunction or not working as properly as it should as described by the OP, as mentioned before it is a trans problem and it is a common fault which affects all models basic through to AMG's.

BC MB

Well said.