Sounds like the issue I had....There is a TSB on this about mounts.
First I tried what some on here said worked..spraying lube in proper mount locations...NOT
Then I tried the sway bar mounts...$18 from Lexus and about 25 minutes to install....NOT
Lastly, I just replaced both front struts (KYB: GR-2), Lower insulators (Lexus/toyo part), upper insulators (Lexus/toyo part), bump stops (Lexus/toyo part), Seat Backs (Lexus/toyo part), mount plate (Lexus/toyo part) and lasty the new-and-improved mounts(Lexus/toyo part), ...NOISE GONE...
Took about 1 hour to remove all and install new.
Well worth the $420 for all the parts to my door. Lexus wanted over 1,000 to do...