Folks,

I've noticed that when under hard acceleration, from a dead stop, there is a "clunk". It's felt, not heard. It's coming from the rear, and feels like the axle/rear suspension is moving backwards. Not much - probably just a small distance. Once it "settles", there is no more action. I cannot feel it move "forward" under braking, nor is it noticeable under light to medium throttle.

It's only when you're at a dead stop, and give it the beans. It's fairly consistent. It's not 100%, but close to 80% of the time.

Is this normal? Anyone else experienced this?

Thanks!

 

Hardly think it has anything to do with chassis or suspension. Unless the car was in an accident before.

One thing you can do is, open up your trunk and tighten the spare tire real good. And also tighten up the stand jack very good.

Those might be loose and will wiggle at times.

 

How old is the car? How many miles? I would look at the motor mounts. At about 10 years and / or 150k miles the LS needs them

 

Engine mounts probably.

Mine did the same thing and the mounts fixed the problem.

 

Okay. Thanks guys. I'll have the mechanic check the mounts when it's in the next time.

It just crossed 120k, and it is 10 years old...

 

That was a great suggestion. If that full size spare isn't screwed down snuggly, I can imagine it shifting when stomping on it. Motor mount(s) is also an interesting suggestion, although I would have thought a noise/sound would appear to originate from the front of the car? <---notice the question mark.

 

How many miles does your LS have? I've seen worn U-joints or driveshaft slip yolk do this on other vehicles.

 

Did you get any resolution on this one? I have a 2001 LS430 with 132K on it, and mine just started this same sort of clunk or skip in the last couple of weeks. If you drive "normally" there is no issue. Only when doing full-throttle starts from a dead stop (don't ask why - I'm a grey-hair and my 430 still sees red-line daily).

 

driveshaft? might be your strut mounts too

 

Cause it's fun... :-)

No - I've not dug into it... Talked to my mechanic. Still need to check the spare tire...

At some point in the next month I'll look into it and report back.

 

I can tell you for certain that it is not my spare tire. I checked it on Saturday and all is really tight back there.

I've had this 430 since new, and I'm trying to decide where to draw the line on repair dollars versus replacing the car with another Lexus. (This is my 3rd Lex over the last 20 years. Why change?)

 

With any luck, it's an engine/transmission mount issue.

but my man, you're killing it! I hope I'm like you when I turn to grey.

Please tell me you also do doughnuts when it snows and can afford a new Lexus but you're like 'forget that noise, I got one that works basically fine'.

And if you've been divorced once and crack ex-wife jokes, you're basically my role model.

 

I'm going to get the car in to my long-time Lexus dealer (Woodfield Lexus, Schaumburg, IL), and see what's up. I don't think I want to move on to another car just yet, as this one is not fully consumed. Turned 133K today, and yes, I do happily drift around corners in the winter - even turn off trac for that.

Speaking of trac - when that kid in the 5.0 Mustang pulls up next to me at a light, I reach down and turn off the trac control then, too. Nothing is more frustrating than pulling a great hole shot on the kid and then having the nanny shut me down.

I could buy a new Lexus, but I just like this one so much I have no real incentive to do that. The 430 is so smooth and quiet, even after all these miles, and even with the 10-inch wide Z-rated tires I use in the summer.

I'll post back once I get a definitive diagnosis.

Oh, one more thing - no divorce here. Married to the same wife for over 35 years.

 

Sounds like a good life... I'm a lot younger... but I drive mine pretty aggressively. Plan on keeping it for about 100k - or roughly 2.5 years... not sure what will follow...

How do the 10" tires do in the summer?? I feel like this car could easily handle another 20-30mm of tire width at each corner. The dynamics are shockingly good, even with 17" rubber and "skinny" tires on it... makes me wonder what a lot more rubber, and a little less sidewall would gain...

I probably won't change mine (I'm a frugal fella, and lets face it, I don't *need* to go any faster around that on-ramp...) But curious minds do wonder...

 

On Ramps R Us! I have Dunlop SP-5000's on the car, IIRC they are 245-55 X 17, on stock 2004 version 17-inch rims. These tires are definitely beefy, and I have no trace of wheel spin on anything short of full-throttle brake-torqueing. If I just let off the brakes and hammer the throttle, the car simply launches with no drama at all. I used to be an avid auto-cross driver, driving a car with modified suspension and all the go-fasters, but now I just have my daily driver, so I wanted to enjoy it to the max. It corners far better than most large luxury sedans could ever hope for. For winter I run Bridgestone Blizzaks on the original 16-inch Lexus wheels (these are 235-60 X 16), and we do just fine.

THE DIAGNOSIS IS CONFIRMED:

The car is at the dealer now, and the "thunk" sound/feeling is most definitely caused by two totally wasted engine mounts. Cost to replace both is about $1,060 before discounts (dealer gives 10% discount if you have over 100K miles on the clock). I'll have the car back tomorrow if all goes well, and will see how much difference the mounts make.