GX550 Overtrail Vibration

[Watchthis]

First things first. What is your tire pressure set at? Mine was at 40psi all around when I picked up my OT. Secondly, tires are probably a bit flat from sitting on boats/at port etc so give it some time to smooth out. Thirdly, request a Road Force Balance from dealership. Best of luck!

Tire pressure was around 40. I dropped it to 35 - no different.
Master tech drove car with me - he could feel it. Did road force and found both back tires to have flat sports. Replaced with two new tires - no different.
I drove their test Premium trim - felt similar, maybe a little less pronounced (it also had the rough transmission shifts).
The master tech agreed with me that its rough, but said it seems to be how they all are. He said they've been getting a lot of complaints about it.
Seems like it's the luck of the draw. Feels rather hopeless. Though I did see that you and another owner had luck with the ride smoothening out after a couple thousand miles.

 

[incognito.gx]

Was the vibration you had the jittery rear axle vibrations, most notable from 10 - 50 mph?
Similar to explained here @ 09:40:

Yes. Although I do believe its related to the Adaptive Variable Suspension but Lexus is telling dealers its tire related to save face

 

[Watchthis]

Yes. Although I do believe its related to the Adaptive Variable Suspension but Lexus is telling dealers its tire related to save face

I wonder if it's an E-KDSS issue. Another user reported that aftermarket lift and 35" tires still had the same issue. The fact that yours went away makes it sound like maybe bushings got broken in/loosened up, allowing the suspension to function as intended.
Hopefully Lexus gets this figured out with a T-SB soon. Or at least gets dealers start acknowledging that it's not "normal."