Hard Acceleration - Clunk Noise

[Gas Guzzler]

Does anyone notice a "clunk" noise when accelerating hard? Noise is coming from the underside front passenger side. It sounds like a heavy metal piece is sliding around in the frunk so I removed everything from the vehicle to make sure. Any hard acceleration forward/reverse has the same noise. I brought my car into the SC to fix a long list of small items and the loaner MS with only 1k of mileage has the same issue.

The list of problems and noises from my MX seems to be getting longer with every visit to the SC. This is the 3rd time my car has been at the SC and I've put more miles in their loaners than my own car. Ugh.

 

[gekkota]

I had what sounds like the exact same thing on my July refresh MS90D. Here is what resolved it:

--------------
Verified customer's concern. There is a clunk noise coming from front of vehicle on
acceleration. Checked suspension components, torque on suspension and chassis bolts.
Noise still present.
Checked right side motor mount clearance - out of spec. Adjusted clearances on front
drive unit motor mount - noise is still present. Performed front drive unit mount diagnosis
procedure and found excessive play on rear bushing of right side motor mount.Right side
motor mount needs to be replaced and DU position re-adjusted.
Corrections: Upgrade Front RH Motor Mount, Adjust LH Mount
Replaced right side motor mount on front drive unit. Verified that clunk from front of vehicle
is no longer present.
Part Quantity
TORQUE REACTION ARM ASSEMBLY
(1052783-00-B)
1
BOLT HF M10x90 PC109 (1050057-00-B) 4
Parts Replaced or Added
Corrections: HV Battery Assembly (Remove and Install)
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[Gas Guzzler]

Thanks so much for your input! I'm going to send over this info and hope that'll make their investigation and repair easier. I've read elsewhere about bushing problems and hope this is not a larger problem that can't be fixed. Extended warranty here I come....

 

[gekkota]

No problem - eager to see if your issue is a match.

 

[CurrentRide]

I found this thread by searching "acceleration noise." I would describe the exact sound on my MX with about 6K miles on it, increasingly noticeable over the last 3 weeks. It is only apparent on hard acceleration from low speeds (or a stop), and does not seem to occur after the car has been driving for a while, almost like it has "warmed up." I will limit my insane launches for now and call the service center.

 

[CurrentRide]

So, the SC suggested that I test this at different suspension levels. It does not occur at low or very low suspension, but does when set to "high." Since I had the suspension set to high based on geolocation, then to automatically lower at 50mph, I was fooled into thinking that it was only associated with the speed and would stop when the car warmed up. I think that adding air to the tires also decreased the volume of the clunking noise even at "high." We had a couple of cold days when the pressure dropped to 38 PSI, which may have compounded the problem.

 

[Blastphemy]

I noticed this same noise, recently. It sounded more like a short grinding noise to me, however. I heard the same noise under the front passenger side when I first got in the car while it was at low suspension and reversed out of my garage. Felt like the brakes were mechanically braking on old, rough pads. Very strange. My X is in the shop for other issues, but I made sure to mention this to the technician. Of course, I couldn't reproduce it on the quick drive we took!