UPDATE! The rattle has been fixed by our dealer...See below!...Our 2021 RX350 has a rattle under the dash at 40-45 mph only. It's speed related, not engine rpm. I've checked the cabin air filter and the glove compartment for anything loose. ECO-Normal-Sport, no effect. A/C on/off, no effect. I have not called the dealer yet. Does anyone have any ideas as to what it might be? The sound is very soft. Not complaining, just wondering. Ray A.

 

A friend of mine bought a new Ford a few years back and there was a rattle in the drivers door. They took the door apart and there was an empty whiskey bottle in there.

 

When you have the glove compartment out, can you feel around in the dash for something that might be loose?

 

The short answer is yes. With the glove compartment off, there's only access to the cabin air filter and two wire connectors to the right. With the cabin filter out, I searched the fan area with a mirror and flashlight. Couldn't see anything loose, but couldn't see much anyway.
Update: I just went to look at the air intakes by the windshield wipers and found two dried leaves thereon. My wife, with excellent hearing, will drive the car today to see if the leaf removal makes a difference. If so, this would be similar to the whiskey bottle in the door story. I will update as necessary.
PS The cabin air filter is huge compared to the one on my '11 RX.

 

We took our baby to Lexus Of Sacramento yesterday and told them about our "rattle" at 40-45 mph. They went thru the whole car. From the receipt: Checked the struts and springs, removed windshield wipers and cowl cover. Road test, still heard noise. Removed glove box, installed "chassis ears" on sway bar end link, sub frame and sub frame mount. Road tested again, when rattle presented, not heard on chassis ears. Loosened and tightened sub frame and bracket bolts. Road tested with another tech and found loose cross bar cover. Added felt to cover and reinstalled. These guys went all out to solve the problem and we are very grateful. This was the best dealer service I've ever gotten in my life, ever!
After all that, the infotainment lady helped my wife with the A/C settings, freeway off-ramp setting and of course pairing the phones. Thank you Lexus Of Sacramento!

 

Same issue. When I sway left and right I can hear something rolling and hitting inside the passenger dash. Scheduled an appointment for tomorrow. RX 305 2021

 

My RX 350 2021 with 1800 miles has something inside the passenger side dash rolling left and right. When I sway the car left and right I can hear something rolling/moving left and right and hitting at the end. On bumps, I can hear a rattle on the same spot. Already removed everything from the glovebox. Has anybody experienced this issue? Already scheduled an appointment with the dealer for tomorrow. Just curious if anybody has the same issue.

 

Sound can travel in strange ways inside the car. But have you checked the air intake vents outside? Between the windshield and the engine bay. Maybe some pebbles/debris is stuck in the grooves or vents.

 

The glove box is pretty easy to remove -- google or youtube can show you how (it has to come out to change the cabin air filter). You can probably avoid the trip to the dealer and the thumb twiddling while you wait.

 

Already removed and checked the filter. Nothing was in there.

 

Here is a video.

https://imgur.com/a/dRQg5Se

 

Just for the heck of it, do you have anything in the overhead compartment where sunglasses would go?

 

Just came back from the Dealership… uh… so… yea, damn sunglasses lol. I did not know there were sunglasses up there because my wife is the main driver lol. At least it was a quick trip. The Lexus tech was happy too lol

 

The reason I mentioned it because the same thing happened to me, every time I took a corner, the sunglasses would slide from one side to the other. Drove me nuts for several days.
I put some foam pieces on each side and now back to quiet!

 

Plee82 - Thanks for the video and the follow-up. I'm trying to make up a joke about Maui Jim sunglasses not rattling, but it's just not there. : )
Ray A.