There is almost no information on this issue. Am I the only one? Car feels like it goes over rumble strips under heavy acceleration from a stop, and during the 1-2 shift.

 

Check converter slip %

 

Not seeing that value anywhere in techstream

 

Use Autel. Techstream is clunky and hard to navigate but it's in there if you look around

 

Torque Converter shudder. Check your fluid or have it checked. If its had regular services/fluid changes throughout its life, service it again. If not, don't f-with it, just get a new trans and converter, cause your converter probably sent material through the rest of the trans and itll follow behind quickly.

 

Prior owner had Lexus install a brand new transmission 25k ago.

 

then the converter is bad. they probably didn't change it (swapped it from old trans and you can't clean them out so it shot old shat through the trans-either way, no bueno)

 

So the floppy rear diff as shown in the video is normal and not likely to be causing any of this?

 

I have the same vibration and shutter in my 2015 LS460 (50k miles and purchased last year as 2nd owner). I have had the dealership look at it and they said this is "normal" for this car. My own mechanic test drove it and looked everything over, said everything looks to be in good working order. I'm struggling to find a fix and the shaking on occasion is really bad intermittently. I have scoured this forum and the internet trying to find a similar complaint with a confident and precise solution. This may be the best direction I get, idk.

 

Compare your diff bushings with my video and let me know what you find.

 

Great video. I have an 08 LS600 and it sometimes has the vibrations/shaking feeling only when cruising at 70 mph +. It's not voilent or anything crazy but it is noticeable. I had been trying to figure what it could be? My tires are all even and no inner tire wear. I have yet to balance them first as I have not balanced them for the past 10k miles. Odd thing is its random? Sometimes it does it, sometimes it doesn't. Its probably time for me to check all suspension components and get all the bushings and all control arms looked into.

 

Yep. Same thing here. i can see the passenger seat shaking. The vibration exists at lower speeds, but is barely noticeable. Around 80 it's very noticable. At 85-90 its conpletely gone.