I have a 2001 LS430 with 104k miles and the sports suspension. Since I bought the car a year ago, there's been a persistent clunking when going over small bumps/imperfections in the road and seams. There's also play in the steering wheel at any angle and, when going over these small bumps, the wheel will actually jerk around and move sometimes. When I turn the wheel back and forth rapidly while sitting in place, there is a clunking as well, though it's not as loud as the particular noise I hear over bumps. Finally, the car wanders at highway speeds (the faster you go, the worse it is). I've had the LCA bushings replaced and it did nothing to reduce the noise so I'm turning to here to figure out what it could be before I throw the parts cannon at it. My mechanic has also taken a look at it and couldn't find what particularly could be causing the noise.

I've been considering it could be upper control arms since the sport models had slightly different UCA's and bushings, so maybe they wore out, but I've considered also if it could be the steering rack and its respective bushings instead. Any thoughts?

 

i would get the car up on a lift and check all the front suspension bushings.
The steering wheel shake is another issue, and im sorry to say there's no easy fix

 

Have an alignment check done and they can determine the worn parts. Most don't charge for check as they hope you will let them fix.

 

I encountered a similar shake issue, and ended up packing the intermediate shaft with Urea Grease, and that has seemed to have done the trick over the last year and 20k+ miles.

 

Steering wheel jerking over bumps is often a sign of "bump steer" and could indicate worn front struts.

Check for additional play in ball joints and tie rod ends.

 

Is the OE grease urea?

 

Unsure. It was pretty dry when I had disassembled it. I had a few pots of it laying around since I became familiar with it from my S2000

 

I did the same around 100K with thick wheel bearing grease, along with replacing upper control arms. Now its probably time to do it again at 180K since the same symptoms are back

 

I'm used to the term intermediate shaft just being a shaft with a u-joint at either end, so how are you guys packing these? Do you mean on the splines where the steering column and steering rack mate with the IS?

 

Go to around 18:00 in the video.

The shaft inside the column is two piece, grease where they spline together. Remove the wheel, snap ring and upper shaft assembly. You can do this without taking the column out of the car.

 

Oh boy that looks like a ridiculous amount of work. At that point I should just ask my indy to replace the whole steering column, no?