01 lexus gs 300. always makes a thumping noise over many bumps , large or small and even at very low speed like 5-10 mph. i just had upper control arms replaced 2 days ago and was expecting the noise to be gone but it it now more frequent and also now slightly happening on the right side also. Its always been on the left side. i bought the car with 83000 miles on it. now have about 143000. ok so i found the 01 is 2nd generation

Got the same thumping noise issue in the right rear of my 2000 GS400...

Anyone???

Maybe you need to replace both front and rear shocks.

Check your caster arm bushings in the front and the the rear stub bushings, which can also cause major clunking

Yup. Should have replaced caster/trailing arm bushings, along with steering rack bushings, spay bar end links... Oh and your tie rods as well. It's all cheap. Easy to do as well.
Edit* except the trailing arm bushings, those are a major problem with our cars. But getting the ones in, out, is tough. I've got a set with the originals already removed, let me know if your interested.

thanks gsgenesis for your information. what kinda of price we looking at to have the work done and with purchase of yours

i dont think its shocks cause i get a nice ride out of the car, its this over uneven surfaces that it happens, some bumps its ok and others its not. tonight i wasnt hitting bumps as much as an uneven road surface and it was clunking from the front like crazy. and its always just in the front , almost like somethings loose and bouncing around under the hood.

worn engine mounts?

Could be! Good suggestion for sure, Would def. Be able to narrow that down at start up and shut down to help you figure that out, but if it's something to do with suspension, most of the time more or less, you can usually kinda pin point if it's coming from where you know...

But How much would I want for the trailing arms though was your question? Or do you mean just in general total price, with mine as well? What years your car again? Anyhow I'll toss your way for peanuts man... Not really a big deal... Would like to hear that you over came this noise is more like it. I battled it as well. Shoot me another PM, are you pretty mechanically inclined? This front end overhaul really isn't hard, like I've said though with other things, nothing... Is hard.... It's just time consuming for both preparation, as far a studying goes if your one thats never touched a wrench, and of course the work. But none of it's "hard"... Anyone here that puts there mind to it, can overcome any issue that may arise, all it takes is patience, and the tools. First timer with good instruction can do this job in a day no problem confidently, checking it twice. Most just don't have the time for it which is unfortunate, that's all...

Strut mounts possibly? My car does the same thing, it's butter smooth driving but I get the clunks at low speeds going over bumps or up my driveway

hey lucas, sounds very similar to my noise.

so why did the noise get worse, more frequent, after having the upper control arms replaced?

If u haven't replaced the lower ball joints I would check those ASAP and put the car on a lift and make sure everything is tight if the ball joints weren't replaced that u know if get it done NOW!, also check the strut mounts. Ps: it is NOT engine mounts that is not a sign of worn engine mounts, at a stop with quick acceleration you will hear a thump also at red lights your whole car and steering wheel would shake...

thanks for that info. it doesnt shake at red lights , so thats good. wonder why my guy didnt do that. , replace lower ball joints that is, huh.

Exactly what's happened to me, lexus had told me twice I needed new upper control arms/ balljoints and since I occasionally heard this I replaced them, 750$ just for the oem parts, when I had them done at the shop they said there wasn't even much play at all In the old ones, car felt a little more solid but now I'm getting these low speed noises more frequently also, the previous owner changed lower ball joints and inner tie rods like 50k ago so I don't think it's either of those..