I have just completed the painful process of refreshing the 200k suspension on my '06 LS430 ML. Based on the advice I have read, I have decided to take the hit and go OEM parts on the majority of the parts I have replaced. After picking up the car from my mechanic who did the work I am noticing and feeling there is still an annoying slight bump/thumping feel to what I am perceiving to be in the front part of the suspension of the car when I go over normal bumps in the road at moderate speeds (city/town driving). I took it back and had him take it for a drive and he said he could notice it as well but wasn't sure what more could be done since we replaced literally all of the parts that could possibly be creating the sound/feel to which I agree. I just had brand new tires put on and also had a full brake job done during the suspension replacement. Here is a list of parts that I have installed.

-**OEM Upper control arms #48630-59045(LH) & #48610-59045(RH)
-OEM Front Stabilizer Link Assy #48820-5002 (x2)
-OEM Rear Stabilizer Link Assy #48840-50010 & #48840-50030
-Front Sway Bar Link Bushings
-OEM Front Lower Ball Joints #43330-59125 & #43340-59125
-OEM Front Lower Arm Bushings #48655-50012 (x2)

Rock Auto
-KYB Excel-G Front Struts #341392 (x2)
-KYB Excel-G Rear Struts #341393 (x2)
-KYB Shock/Strut Mount Front #SM5565
-KYB Shock/Strut Mount Rear #SM5566

After my roughly $4k spend and literally all parts (front) replaced as well as struts plus stabilizer links in the rear I was expecting to be more pleased than I am as a result of the bump/thumping sound/feel my mechanic and I agree seems to be in the front of the car.

My questions are this.....
#1 did I make a mistake going with the KYB strut tops rather than than OEM #48680-50110 replacements?
**#2 (which I'm just noticing as I am tying this) does it matter if the upper control arms are for a car with a sport pkg vs one without? I just saw that the part numbers I have shown in my list are indeed for a sport suspension whereas my car does not have said sport pkg (at least I think) which shows the correct part numbers as #48630-59035 & 48610-59035.

The car rides and drives incredibly better than before these improvements. Very smooth and tight however I feel it should not be giving the bumping/thumping sound that is still so annoying and should have a more solid feel in the steering wheel while driving.

Note: I am running 32lbs of tire pressure in the brand new Falken Aklimate tires.

 

You left out one bushing (see pic). The front LCA bushing, which is not available individually from Lexus. I think Febest is the only source- TAB-374-KIT

I'm not entirely familiar with the KYB mount, but to the best of my knowledge, it's a similar design to the genuine Toyota/Lexus part but not the same quality.
The OE part has a VERY thick layer of rubber/cushion atop the bellow where the spring meets the mount. The KYB part is likely made cheaper where it counts.

Also, if we're talking bump/thump/clunk, don't forget the steering rack bushings and wheel bearings.

 

Ok, well since Bradland replied, that shortens my response. He has thorough knowledge. A clunk does sound like a bushing, but I would not have known there was one left out so I think that is a good direction to go.

My 2 cents: KYB did make the OE struts for these cars, but that does not mean the KYB strut you buy aftermarket is the same as the one that was original, so I completely agree with him above. Now, that being said I don't think that's the issue; lots of people have gone aftermarket on struts on here and been satisfied. The OEM's last longer, but at 200k, do you really need them to last as long as the originals?

As to your sport suspension question, I have no answer but that is interesting. Hopefully some others will chime in. Was the sport suspension available on 04-06? I don't recall, but seems like there should be a little plate on the car that states it. Lexus.com has become increasingly unhelpful for details but if you registered an account and plugged your VIN in they might still indicate if it has it. @bradland , is there any logic to my thinking that if he got a control arm that was made for a tighter suspension, it is possibly allowing too much play in the tie rods or steering rack or struts?

 

As a follow up.....I just realized that I did not replace the other (small) bushings in the lower control arms. I was not able to locate an OEM part number for this bushing however I did find what I believe to be a decent aftermarket set. In hindsight, it appears that the best course would've probably been to replace the entire control arm which I am unwilling to do at this point especially since I already replaced the larger bushing with an OEM one in the OEM control arm. Hopefully this works. I was also able to go to chatGPT and research the different part numbers for the upper control arm question (sport pkg vs not) and I believe I am ok with the ones I now have installed. My car does have "18 factory wheels (which is a clue for a sport pkg) but after purchasing a Monroney label I discovered the wheel pkg was added as an installed option from Lexus when the car was ordered and that I do not have a sport pkg on my car.

 

Thanks so much for your quick response which I unfortunately didn't see until after my response below. I will start with the smaller bushing and go from there. I pray I do not have to have it realigned a second time and waste another $125 but I gotta get this right. Hate to come this far and hate driving the car. because of a simple fix. Hopefully it won't come down to the strut mounts having to be replaced with OEM since they are brand new.

 

Good catch on the 18's, true they do not automatically mean Sport suspension.
I did a big refresh like this 2 years ago and I did do both sets of bushings, now that I see my receipts.

 

I believe the Car Care Nut has solved the problem you have
it is way above my level
I believe it concerns the steering column, steering shaft,
I tried to watch his video, but like I said, way above my head