Subtle Vibration and Random Metallic Noise

[BinaryExpert]

Thanks all for sharing helpful information and helping others.

I bought a new 2019 Expy Max Platinum 3 months ago and drove about 6100 miles so far. Started from about 3 weeks ago, it does not drive as solid/quiet/smooth as before. I feel a very subtle vibration continuously coming from the bottom of the car (feel more clearly from acceleration pedal and a bit from steering wheel as well). It feels like a subtle metal grinding (and possibly dragging although I can't tell) and I feel it better when the car is coasting straight at low speed in the morning. Although I don't hear anymore, I (and my wife) also heard several times a pretty loud metallic noise/rattle for a very short period time (1~2 second). I suspect this is how it started. They don't seem to be related to steering/acceleration/braking as they are pronounced when the car is coasting straight. The speed does not seem to be related either. I still hear a small (not loud anymore) random metallic noise from the bottom from time to time mostly in the morning.

From symptoms, I suspect u-joint, brake disc/rotor, shaft connections or lack of lubrication, but it could be a completely different thing as the car mechanics are complex. Any advice or suggestions?

 

[AAOO]

2WD or 4WD?

 

[BinaryExpert]

I always drive in 2H. I tried 4A but no difference at all. Thanks anyway.

 

[aggiegrad05]

https://static.nhtsa.gov/odi/tsbs/2018/MC-10149748-9999.pdf

Check out that link. That is why he asked if you have a 2wd or a 4wd (I think). I had the same issue with mine.

 

[BinaryExpert]

Oh.. Thank you so so so much! I just made a service appointment, and will post any result here.

 

[AAOO]

https://static.nhtsa.gov/odi/tsbs/2018/MC-10149748-9999.pdf

Check out that link. That is why he asked if you have a 2wd or a 4wdc (I think). I had the same issue with mine.

Exactly why I asked. Thanks for posting aggie!

 

[BinaryExpert]

I just got back from my test drive in 4A, and am very disappointed. It still happened in 4A. Is it possible this exact problem could happen in 4A (if engaging/disenganging is not perfect, maybe)?
I also found this interesting YouTube

 

[BinaryExpert]

I just got back from my test drive in 4A, and am very disappointed. It still happened in 4A. Is it possible this exact problem could happen in 4A (if engaging/disenganging is not perfect, maybe)?
I also found this interesting YouTube

 

[aggiegrad05]

I just got back from my test drive in 4A, and am very disappointed. It still happened in 4A. Is it possible this exact problem could happen in 4A (if engaging/disenganging is not perfect, maybe)?
I also found this interesting YouTube

Honestly, I don’t remember if mine happened in 4 as well or just 2. I THINK it was both because it’s an engagement issue, but possibly not because the issue stems from the fact the system can’t hold in 2 and slips into 4; so if you’re choosing 4 I would think the issue would not present.

But I just don’t remember, I’m sorry.

 

[BinaryExpert]

Thanks Aggie. You helped me a lot already. BTW, I tried to record the sound this morning to show to a technician tomorrow, and the grinding noise/vibration seemed to get worse since my 2H/4A test yesterday. It happens as much or more in 4A as in 2H. The sound is recorded but it is not crystal clear when I replay.
On a slightly different note, I made an appointment at different dealership this time as I don't like the dealership where I bought the car. Is there any danger in this change with respect to warranty coverage? Any advice would appreciated. Thanks!