[AEMontoya]

The noise only presents when turning the wheel. When going straight back, or even going back at a variety of angles, the noise does not occur. Additionally, if I am stationary, and turn the wheels full deflection in both directions, the noise does not occur, even after numerous turning at different rates. The noise only seems to occur when backing up and turning the wheel, with the noise happening when the wheel deflection reaches about 3/4-4/5 full travel.

As an added note, the sound does not occur every time.

I'll try to experiment some more with it today.

 

[AEMontoya]

Interesting. I do have the 20" tires, but the noise definitely does not present at full turn, and it's definitely some sort of knock coming front underneath, as if some sort of linkage or drive issue.

 

[AEMontoya]

This could be the transmission shaft ... worst case. But you may want to look up Akerman steering.

Dear Lord ... don't scare me. I can't imagine that for a vehicle with only 6k miles that seems to have been babied by the previous owner. Luckily, I did purchase a warranty for it, and I plan to take it into the dealer to investigate why a "Lane Keeping Assist Inoperative" fault gets thrown every once in a while. I guess I'll ask them to look into the noise while they're at it. In the end, there must be something that isn't right, since no one else is indicating that their GLA makes the noise too. Then again, this vehicle does have the AMG Dynamic Package, which I'm guessing most GLAs don't have, and this package introduces a limited slip differential lock (but, it'd be weird to me to think of a vehicle whose inherent design allows for a knocking noise from time to time when reversing and turning the wheel).

 

[AEMontoya]

Yeah, I just watched a few videos on Ackerman steering, but didn't go too deep into how it might relate to my issue. I began that search and came across so many other potential causes that I threw in the towel, for tonight at least.

 

[AEMontoya]

Update ...
After driving the vehicle some more, it seems that the noise pretty much only presents itself when reversing out of the driveway slowly and turning the wheel rather quickly at the begining of the day (i.e., after the car was sitting throughout the night--temps in high 50s throughout the night and mid 70s during the day). I don't remember being able to recreate the noise later in the day. Additionally, if I turn the wheel more slowly as I back up, or back up more quickly as I turn the wheel more slowly, it doesn't seem that the noise presents. Will keep testing.

 

[AEMontoya]

That is completely normal.

That's good to hear. I looked into Ackerman steering some more, and it does sound like it might fit the bill. Thanks.

 

[AEMontoya]

Hi, congratulations on the new vehicle! I haven't definitively figured out what causes the noise, but I'm beginning to think that it's normal, given the research I've done. I know that I certainly don't notice any adverse effects, beyond the noise. And, if I turn the wheel more slowly while reversing, such that there's not so much tension on the steering mechanic, then the sound never occurs.

 

[AEMontoya]

Interesting ... I'll try turning traction control off too, and will report back. Does your vehicle, by any chance, have the Dynamic Plus Package, which has a limited slip differential lock? If you don't have the build sheet handy, I suppose the easiest way to find out is to see if your driving mode dial has a Race mode (although, I think it might be possible to option Race mode, a la carte, without the DPP and the LSD). I was wondering for a while there if the limited slip differential could be related.

 

[AEMontoya]

Very nice! Our vehicles are very similar! Race mode is a blast! I keep reminding myself to take it easy so that I don't become a nuisance on the road or get into trouble with the law. You might consider adding some of your vehicle's details below your post, like I did. Allows everyone to immediately know what they're dealing with. We should keep in touch about how we accessorize ours over the next few months. I'll definitely let you know more about what I find out about the noise.

Here are some ways I've been accessorizing mine over the past few weeks:

-replacement of cheap plastic door lock pins with brushed steel AMG pins (not OEM MBZ, but very high quality Japanese ones with AMG logo).
-powder coated AMG license plate shrouds (going to get custom plates as soon as possible)
-installation of front/rear dashcam
-outfitting the vehicle with roadside assistance stuff: compact battery starter, MBZ Jack, spare fuses, tire repair plugs, emergency roadside led magnetic flares, ... Also added music library (from iTunes) on tiny thumb drive installed in USB port, window tint, phone mount, ... I also found a nice bike hitch for the vehicle, but have decided to hold off on installing right now.

The one thing I'm pursuing hard right now is activation of Android Auto on my head unit. Mine didn't come with it, and I've been messing with the head unit programming to try to get it. I've been calling dealerships, but none of the sales associates or service techs seem to know much.

Anyway, keep in touch.

 

[AEMontoya]

@Wayne
Thanks!