2012 merc amg

On my 2019 Cabriolet sometimes when I shift into reverse it makes a real clunk sound. It seems the eco is shutting off the motor and restarting it right when I shift to reverse or something. Gonna really start observing it's behavior and watch the tach to see if this is exactly what's going on. If I shift back and forth between drive and reverse I can't seem to get it to do this. I think maybe there is some kind of software glitch. Anyone else have this issue with either a sedan, wagon or cabriolet E450? It's a really noticeable clunking the car lurches. At first I thought maybe a bad u Joint as the car is 2WD but I don't think thats it, hopefully not. 780 miles on the car right now.

SCRL

bytemaster0

Do you hear it when in the car with the windows up? Or do you have to be in an enclosed space, or have the windows open?

2012 merc amg

No, you can feel it big time, feels like another car bumped into the car. Ya, I think there is a issue, I have a 2019 E450 Wagon and it does not do this at all. I need to feel out the situation more and if I don't come to any conclusions time to make an appointment at the dealer. Was hoping to maybe wait till the 10K oil change service but this is not a normal thing and thats going to be a long while as I'll be driving this car under 10K miles per year.

rustybear3

Yeah, that's not normal. I have the same 2RWD configuration and I experience nothing like that. I would definitely get it into the dealer ASAP! Don't want your transmission going out on ya.

2012 merc amg

Thanks, ya, it can't be good for the trans. I think the auto start feature is bump starting it when I go into reverse and starting when it's in gear already. At least thats what it feels like. Doing a small trip tomorrow, I'll really try to figure out what it's doing when it happens then and make an appointment at the dealer.

nycebo

I don't feel a clunk going into reverse, but it sure is grabby on my wagon. Have to be very gentle with the throttle .

bytemaster0

Sorry to hear that. Definitely not normal for what I've seen. If you disable auto start/stop, does it still occur?

2012 merc amg

stephos

Not had this happen on my E450 coupe 4matic.

Really does not sound normal at all based on your description. The fact that you've not had this problem on your wagon suggests that it might be specific to your cabrio.

Definitely monitor more closely and report back.

2012 merc amg

Definitely related to the auto engine stop/start feature. Only clunks going to reverse when the engine has shut down which it seems to do a lot when shifted to neutral. I'll see if my wagon shuts off tomorrow when shifted to neutral, I'd think if anything it should start again when shifted to neutral. Does not do this at all when in neutral with the auto stop engaged and shifting to Drive. Nor does it do it if the Auto stop feature is turned off with the button with the green light on the center console or with the car in sport plus mode. So definitely looks to be a software issue. I think it's something that can wait until my 10K service. Also the drivers side sunvisor mirror light is not working properly either so I'll get that fixed at the 10k service too. I'm debating on whether to try resetting the throttle calibrations to see if that might fix this issue.

teksurv

WRT to the sunvisor light not working properly, have you tried unhooking it (as if to move to side window) and re-hooking it firmly? I had this issue on my 212, and that was the fix. On the 212 (and many others) there's a metal contact in the hook/hinge for power. I haven't looked on my 238.

2012 merc amg

Yep, did that and still the same, the light flickers on and off as I move the sunshade, it's getting a bad connection. When I get the time I may try taking a small wire brush to the contacts, I'm thinking maybe there is some kind of film on the contacts, thats sure what it seems like. If not I'll get it fixed at the 10K service.

I've pretty much determined this drive line shudder is normal as my wagon does the same thing. It only does it when you shift into reverse when the motor is in the eco stop mode. If someone else can verify the car does this that would be great. When you come to a stop in drive and the motor shuts down in eco mode shift into reverse and your going to get one heck of a shudder, I think part of it is the motor restarting and the other part of it is slop in the driveline going from forward to reverse. If you put it in neutral with the motor off in eco and go back to drive you don't get this, the motor restarts and it's fairly smooth. Leave it to me to find the bugs in these cars, I found lots of them in my AMG wagon and there generally was no solutions. I think the only solution to this issue for now is to hit the eco button before putting it into reverse and that way it will be a smooth transition. Hopefully there will eventually be a software fix for this issue. Reason I noticed it in the Cabriolet first is because I back that car into the garage an stop out in the road and thats when the engine shuts down and then put it in reverse and you get a real semi violent nudge like somebody it the bumper of the car or something. Can't be good for the driveline or the motor mounts.

2012 merc amg

Taking my small pipe cleaner wire brush to the sun shade rear view contacts did the trick, light works fine now. Would like to hear from anyone that has stopped and made sure Eco engine stop has stopped the engine and then put the car into reverse. How much of a jolt did you feel? On both my 2019 E 450 Cabriolet and 2019 E450 Wagon the jolt is pretty substantial to the point where I don't like beating up on the drive train that much and will hit the eco button to restart the engine before putting the car into reverse. Hopefully Benz will come up with some sort of software fix for this in the future. It would be too much of a coincidence if something was wrong with both my 2019's. I suspect all the 2019 E450's do this. My Cabriolet does it worse than my Wagon, I suspect because it's RWD and there is less drivetrain components to absorb the shock.

teksurv

I just tried engaging reverse after ECO shut the engine off. It shook the car a bit more than when in drive and in normal ECO usage, but nothing I would describe as harsh or a jolt.

Alan0354

The transmission shift a few seconds after you push the lever, you might step on the gas too soon and make the clunk sound when it engage at higher engine rpm. Everything is slow in response in the new E class. We don't like the E class nearly as well as our 2014 ML. In the ML, everything is fast, you shift the transmission, it shift instantaneously, not wait for 2 or 3 seconds before it shift.

rbrylaw

I'd get your transmission checked. What you describe in no way resembles my experience in my E450. In fact the transmission is so smooth, I can't feel it change gears at all. Power is instantaneous and smooth.

ua549

Either your car is an exception or the extra power makes it shift smoother. In my E300 I can feel every gear change. It is especially noticeable when it downshifts while slowing for a stop. I can do smoother shifts with a BMW manual transmission.

rbrylaw

I doubt my car is an exception. Our E400 and E450 both shift seamlessly. Perhaps it's the 4 banger E300 which isn't as smooth?

stephos

My E450 shifts perfectly. It's possibly the smoothest transmission I've ever experienced.

2012 merc amg

ua549

Then it must be due to lack of power and vibrations from the 4 cyl engine.

Alan0354

It's normal, everything is slow on that car, even when you change the fan speed, it will take 2 sec for the fan to react. The loaner E300 is like that too. It just test your patience.

I am not complaining about the transmission shift when in drive mode. It's when you go from reverse to drive or drive to reverse, it will take time.

I got spoiled by the 2014 ML350, it's so much smoother, everything is quick in response, you shift from R to D or D to R, it change right a way.

Ryan Shi

Hey did you ever figure out the cause of this issue? I just purchased a 2017 E300 and am having a similar experience whenever I attempt to back out of my driveway. The car will randomly lurch and make a loud grinding noise. It feels like someone is hitting the rear of my car as you described. The problem seems to go away after I put the car in drive then back into reverse. Any advice on what is causing this issue? Thanks a ton

ua549

If you are shifting out of park try manually releasing the parking brake.