My 2013 RX 350 (owned since new and currently with 42k) has, I believe, the very same noise since it was darn near new. The noise sounds to me to be from the transmission. It occurs right at 1700-1800 RPMs WHEN UP SHIFTING under mild acceleration. this is the very same sound one of my old Chrysler's made under the same conditions. i found out that the trans had an external valve body so hearing it was easy. I have no idea if this is the same noise. It has concerned me though I never went to the dealer about it when it was under warranty. can anyone else validate this noise? Should I be concerned? Any help would be much appreciated. Thanks

 

Are you sure it is from the transmission and not the engine ?

 

I can only hear it @ said RPM and right when it is in the process of up shifting. I cannot absolutely rule out that it is from the engine.