I have a basic question that I'm sure is actually a very ambitious project.We have a 2006 Lexus RX330.After 11 years and almost 110,000 miles, things wear out and break down. While the vehicle rides nice and quiet on smooth roads, you hear more knocks and rattles on rougher portions.My question is, what undercarriage parts would I need to replace to get back that new vehicle tightness and smoothness you have when driving over bumps, pot holes and rough roads?

 

Try to isolate the noises as much as possible, front or back & which side.
As I hear an odd thud at times on the passenger rear side when hitting some potholes or bumps...
leads to the possibility of a weak strut or coil spring.
Verify for leaking struts or cracked & heavily rusted coil springs for starters.

 

I was getting a lot of noise from a strut, sway bar links and bushings, and the spare tire. I'm still getting some noises after new struts, but I believe what I'm hearing now is from low-quality struts, as I now have noise on the side where there wasn't any before. It's also possible for a bushing at the bottom of the rear wheel axle carrier to go bad and make noise. I can't find any play in mine, but it's supposed to be tricky to pinpoint sometimes.