New Update On Thump

[GS400jon]

Hmmmm. I know I'm not helping by asking more questions but how did you conclude that the problem you feel is caused by the KDSS? I am not mechanically oriented so relating a problem that feels like a shock absorber to sway bars control is confusing. :(

[denslexusgx470]

that, i truthfully have to say, i don't know! ;) but the tech who did it finally used their knwoledge they learned at Lexus school and finally applied it to my GX! :cheers::cheers:

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Please shed some light on this. What does your repair reciept say??

Thanks in advance.

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alright, i'll go find it when i get home tonight.

[denslexusgx470]

OH MAN! I was gonna post up the service, but i left it in my dad's notebook bag!

but all i know is, they resolved my thump problem, thru another problem. remember my brake leak problem?? well, it turned out that both rear brakes were leaking, causing them to stick sometimes (no wonder i smell them sometimes). Now they fixed the brake leak, surprisingly they also fixed the thump (which was still occuring before i had the brake leak fixed) and so far so good! i'm around 300-400 miles w/o the thump, thanx to a lousy brake leak(s)!

i'll post up the service write-up when my dad gets home! ;)

[ADVocate]

Hmmmm.  I know I'm not helping by asking more questions but how did you conclude that the problem you feel is caused by the KDSS?  I am not mechanically oriented so relating a problem that feels like a shock absorber to sway bars control is confusing.  :(

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The sensation is that of a hydraulic piston releasing pressure. Which is how the KDSS works, by shifting hydraulic fluid to the opposing side/ front to back. It just feels like a sticky piston. As I mentioned earlier, I could be wrong on my conclusion. But, from past experience and some mechanical engineering knowledge. That is my floundering logic. :) I have not been able to reproduce this on command, and it only happens occasionally. Once that is determined, it will be easier to rectify.

[GXRemorse]

Hmmmm.  I know I'm not helping by asking more questions but how did you conclude that the problem you feel is caused by the KDSS?  I am not mechanically oriented so relating a problem that feels like a shock absorber to sway bars control is confusing.   :(

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The sensation is that of a hydraulic piston releasing pressure. Which is how the KDSS works, by shifting hydraulic fluid to the opposing side/ front to back. It just feels like a sticky piston. As I mentioned earlier, I could be wrong on my conclusion. But, from past experience and some mechanical engineering knowledge. That is my floundering logic. :) I have not been able to reproduce this on command, and it only happens occasionally. Once that is determined, it will be easier to rectify.

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The analysis sound good but here's the problem. I don't have the KDSS system and neither do the 2003 and early 2004 owners. This is clearly a problem with the two part shaft system since I can feel the clunk happening under the seats whether I'm sitting in the driver or passenger side.

[GS400jon]

ADVocate, thanks for the additional description of what you are experiencing. I would tend to agree that there may be something going on with the KDSS. The "intermittent" is the bane of the vehicle owner. I think it was invented by the auto dealer as a description of something that can't be duplicated for the service people so it therefore must be normal operation or a creation of the owner's imagination.

Hope you are successful in isolating the problem.

[loki]

ADVocate, thanks for the additional description of what you are experiencing.  I would tend to agree that there may be something going on with the KDSS.  The "intermittent" is the bane of the vehicle owner.  I think it was invented by the auto dealer as a description of something that can't be duplicated for the service people so it therefore must be normal operation or a creation of the owner's imagination. 

Hope you are successful in isolating the problem.

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Hey guys, I'm from t4r.org and I own the gx470's little brother; an 04 4runner. As you might already know, we share the same drivetrain. The thump has been an issue with the 4th gen 4runner also and since they don't have KDSS I tend to think that's not the cause. A few members have gotten some good results by lubing up the drive shaft; apparently it's fairly dry from the factory. The thump will return after a while at which point, lubing up the drive shaft again will quiesce the problem. Hope this helps.

[GS400jon]

I think ADVocate knows what the "thunk" problem is all about and it's not what he's experiencing with his truck.

[denslexusgx470]

I think I'd agree with ADVocate.

sorry i havetnt posted the write-up, still looking 4 it! :whistles:

[smaislin]

My thump is gone. TSIB DL001-04 has been applied providing me with a new driveshaft.

All seems fine. Overall, it was a minor issue for me and now it is no longer an issue. I am happy. :)

[Unlisted]

the problem with these forums is that when your standing around a bunch of people claiming there sick then you must believe your sick also. some have legimate problems and others believe they must have them too. so they drive there gx, rx, es looking for anything they may seem like a clunk, transmission lag etc. Lexus is a customer friendly company. the best in the business. if there is a problem thet fix it. in the engine gel case in the previous es and rx 98 out of every 100 cases had no service history... but they backed it up anyway. automobiles are machines and you can never guarantee they will be perfect. hence warrantys. as far as the gx there are no original parts in the truck . the truck was made from all existing lx and 4 runner parts. so if the problem was widespread it would have surfaced before. i do know they were anxious to put kdss into every gx starting sometime in 05. to improve ride quality. enjoy the 268 good things about the car and try and forget about the 1 thing that comes up only when the car is doing 45 mph during days where the temperature is below 64 degress fahreinheit. as lexus says we pursue perfection so you can pursue living. if its broke they will fix it.

[smaislin]

the problem with these forums is that when your standing around a bunch of people claiming there sick then you must believe your sick also. some have legimate problems  and others believe they must have them too. so they drive there gx, rx, es looking for anything they may seem like a clunk, transmission lag etc. Lexus is a customer friendly company. the best in the business. if there is a problem thet fix it. in the engine gel case in the previous es and rx  98 out of every 100 cases had no service history...  but they backed it up anyway. automobiles are machines and you can never guarantee they will be perfect. hence warrantys. as far as the gx there are no original parts in the truck . the truck was made from all existing lx and 4 runner parts. so if the problem was widespread it would have surfaced before. i do know they were anxious to put kdss into every gx starting sometime in 05. to improve ride quality. enjoy the 268 good things about the car and try and forget about the 1 thing that comes up only when the car is doing 45 mph during days where the temperature is below 64 degress fahreinheit. as lexus says we pursue perfection so you can pursue living. if its broke they will fix it.

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Well, there was a thump and it was significant though not particuarily annoying. I told Lexus that it would be hard to replicate. I also told the service manager not to worry about it unless they knew of a fix that would address it. I did not want them to have to spend time diagnosing something that may not show up. At the time I did not know that others were experience similar symptoms.

You would find, based on a post I put in a couple of months ago, that I find this to be one of the finest automobiles that I have ever had the pleasure to drive. It is simply superb. I plan to also acquire the SC430 while keeping the GX for many, many years as my utilitarian, but luxuious transportation: cycling, canoeing, etc. After driving quite a few European luxury brands over the past 15 years, I find this Lexus as well as Lexus service as second to none. As long as the vehicles are built to the standards that I experience today, I cannot imagine that I will ever purchase another brand.

It is good that Lexus tries extra hard to make me happy. I am very happy and have never been so satisfied with an automobile experience. I tell anyone that asked me for automobile advice to buy a Lexus.

As I also wrote in a previous post, these are very complex machines and to expect perfection is asking too much. However, I do believe that Lexus appears to get closer to perfection than any other brand.

:D

[dbw]

I can cause my GX to do the "thump". I'm a two foot driver, and if I leave my right foot on the accelerator with even the slightest pressure when I come to a stop, I get the thump. It is as though the pressure on the pedal causes the transmission not to fully disengeage. I can also cause it if I am hot rodding and really throw out the anchor to a full stop.

But I've found that if I drive like a gentleman :whistles: , I never notice the thump.

[lonewolf69]

Hi Guys,

Newbie here on Lexus Owners Club forum getting ready to pick up 05' Blizzard Pearl end of month! :) Just wanted to "bump" this and throw this partial review out to the "experienced" GX470 owners here.

Car & Driver mag review (3rd paragraph last two sentences):

"diffs at each end. The Torsen directs more torque to the end with traction, and a traction-control system automatically brakes any spinning wheel, with a noticeable clunk when it kicks in. For extremely slippery situations the center differential can also be locked."

Entire article can be found here:

http://www.caranddriver.com/article.asp?se...3&page_number=1

Could this be the cause of the dreaded "clunking" noise?

[YamaGX470]

interesting point, but that would have been easy to diagnose.

My GX470 has 40,000 miles now and the thump/clunk/kick has worsened again.

The Lexus Customer Service 800# is a waste of time, it takes 2 weeks for a "supervisor" to return your call and asks you to describe the problem without ever reading/researching your complaint. That is bull*BLEEP*.

LEXUS SUCKS! THEY WONT EVEN ADMIT THIS IS A PROBLEM/DEFECT, THEY CLAIM ALL SUVs HAVE THIS "CHARACTERISTIC" !!!!

SHOPPERS, DO NOT BUY THIS SUV UNTIL THIS DEFECT IS FIXED, EVERYONE WILL LIE TO YOU AND CLAIM THERE IS NO ISSUE.

TRUST A BUYER/DRIVER WHO ACTUALLY SPENT THE $ TO BUY THIS SUV OVER A SALESMAN WHO HAS TO SELL A CAR OR A COMPANY WHO WILL LIE TO PROTECT THEIR IMAGE.

THANKS FOR READING...I FELT LIKE VENTING AGAIN AFTER BEING AWAY FROM THIS SITE FOR MONTHS.

[sgriffith]

Does anyone on here have a 2005 model with the "thump" issue? I assume they will still have the problem since a fix hasn't been found. Just wondering....

[flukechance]

Ive got an '05 w/ KDSS and the thump. I don't know if mine is a lot less than everyone else's or not, but I don't really see the issue. It just feels like a downshift, and I only notice it when at a dead stop. Don't want to down play anyone else tho. Maybe their's is worse than mine.

[denslexusgx470]

Ive got an '05 w/ KDSS and the thump.  I don't know if mine is a lot less than everyone else's or not, but I don't really see the issue.  It just feels like a downshift, and I only notice it when at a dead stop.  Don't want to down play anyone else tho.  Maybe their's is worse than mine.

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how early (in mileage) did you feel the thump???

[waynelexusgx470lemon]

I have now had a fifth (5) problem with the drive shaft. It is very irritating. It started on my 03 GX470 at 18,000 miles and only stop"s for about 3,000 miles after repaired or replaced. My Lexus will let me trade but I want a refund less usage. They have denied this request. This vehicle has also had a new transmission at 7,000 miles and 2 CD changers. The left front turn signal goes has gone out for the fifth time. Has anyone received a refund or just lip service?

[cowabunga]

Ive got an '05 w/ KDSS and the thump.  I don't know if mine is a lot less than everyone else's or not, but I don't really see the issue.  It just feels like a downshift, and I only notice it when at a dead stop.  Don't want to down play anyone else tho.  Maybe their's is worse than mine.

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I'm about to get a 2005 without KDSS. I test drove 2 470's at the dealership and was looking for the thump. Neither one had one that I could reproduce. Neither had the steering wheel vibration either. Then again, these issues may manifest further down the road.

What was the build date on your 470?

Is the notorius thump similar to the thump you feel when you accelerate from a dead stop in neutral and with the RPM relatively high, you shift into drive? Does this accurately describe the thump?

[waynelexusgx470lemon]

This is ridiculous, I am warning shoppers/buyers not to buy this GX470 as this driveshaft thump totally ruins the ride, feel, quality.  The mechanic test drove my truck and said this is normal for most SUVs with this type of rear suspension.  This is absurd, they are denying it is a design problem. 

I request that all current owners please join and make a concerted effort for Lexus to take some positive action, either by compensating us, allowing us to trade this defective SUV, or at the very least publicly apologizing and promising to provide a solution to this defective driveshaft design.

We did not pay around $50,000 to deserve such a headache and regrettable mistake.

Please reply to this message by providing your name and vin # perhaps so we can track all the owners with this problem then forward it to Lexus.

We should even consult with an attorney for a possible class-action lawsuit as Lexus corporate is denying that there is a problem.

My email is yamauf@aol.com

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[waynelexusgx470lemon]

My 03 GX 470 is going in for the fifth (5) time on the drive shaft thump. It is very irritating and I am getting nowhere with Lexus. The service manager suggested I sell in the newspaper. I cannot do that to anyone. He offered me a trade in or 36,000 wholesale.

I am ready to park myself in front of the Lexus dealership with a lemon sign until I get their attention. This same vehicle has had a new transmission at 7.800 miles and now needs it's second CD changer. The 6 burned out left turn signal lights is just a bonus.

[indiasfinest]

This is ridiculous, I am warning shoppers/buyers not to buy this GX470 as this driveshaft thump totally ruins the ride, feel, quality.  The mechanic test drove my truck and said this is normal for most SUVs with this type of rear suspension.  This is absurd, they are denying it is a design problem. 

I request that all current owners please join and make a concerted effort for Lexus to take some positive action, either by compensating us, allowing us to trade this defective SUV, or at the very least publicly apologizing and promising to provide a solution to this defective driveshaft design.

We did not pay around $50,000 to deserve such a headache and regrettable mistake.

Please reply to this message by providing your name and vin # perhaps so we can track all the owners with this problem then forward it to Lexus.

We should even consult with an attorney for a possible class-action lawsuit as Lexus corporate is denying that there is a problem.

My email is yamauf@aol.com

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you guys are all over reacting....a little noise when u change the gear? give me a break...your going to sacrifice 60k over a thump? dont complain thats the only problem there is in the car...and its probably the off roading or susupension since the hydraulics turn on and off with the car...and it maybe something with the breaks...

[denslexusgx470]

This is ridiculous, I am warning shoppers/buyers not to buy this GX470 as this driveshaft thump totally ruins the ride, feel, quality.  The mechanic test drove my truck and said this is normal for most SUVs with this type of rear suspension.  This is absurd, they are denying it is a design problem. 

I request that all current owners please join and make a concerted effort for Lexus to take some positive action, either by compensating us, allowing us to trade this defective SUV, or at the very least publicly apologizing and promising to provide a solution to this defective driveshaft design.

We did not pay around $50,000 to deserve such a headache and regrettable mistake.

Please reply to this message by providing your name and vin # perhaps so we can track all the owners with this problem then forward it to Lexus.

We should even consult with an attorney for a possible class-action lawsuit as Lexus corporate is denying that there is a problem.

My email is yamauf@aol.com

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you guys are all over reacting....a little noise when u change the gear? give me a break...your going to sacrifice 60k over a thump? dont complain thats the only problem there is in the car...and its probably the off roading or susupension since the hydraulics turn on and off with the car...and it maybe something with the breaks...

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the problem is caused by the automatic leveling of the rear suspension. constantly, the suspension "adjusts" itself all the time, and at certain times it causes the "thump". now we all know this car costs alot, but we complain about it because this shouldn't happen to this kind of car, and the Lexus brand. :)

[tshrtkng]

I have a MINOR thump in my GX but my wife has a Toyota Sequoia which has a MAJOR THUMP, it is VERY ANNOYING!

The design flaw is obviously in both Toyota and Lexus, Keep an eye out I'll bet that some creative law firm out there will be conjuring up a Class action suit!

Maybe we should start one ourselves!

There may not be anyone who knows the answer to this question, but does the new 4Runner have this same issue?  I was drooling over the GXs until reading all of this & have almost decided to buy a used LC or LX.  But am considering a new 4Runner as well.  Just wanted to see if anyone knew if the problem was there with them also?

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I have not heard anything about the 4Runner having this issue. But, than again, it has only been a few who have had this issue occur on their GX vehicles. There have been discussions about what the problem may be. And some of the owners have said the problem was resolved after the dealer took it in. Perhaps, through a visit or two. I have not had this problem and I now have more than 12K on the truck. Some say that it occurs anytime they drive, and others say only periodically. A lot of it depends on what the owner is expecting, and their sensitivity between a luxury truck and a luxury sedan. I have noticed, on my truck, an occasionaly suspension adjustment after stopping at a light (usually after some hard manuever). This manifests itself as a thump that you feel inside the cabin. The closest I can determine this, is the KDSS suspension correcting the balance of the load through the hydraulic pistons which it incorporates. This does not always happen, and once I determine how to replicate it for the dealer, I will probably have them look into it. This is a curiousity, not necessarily something that drives me crazy. All in all, I still think it's a great truck, and far better quality of components than the 4runner ever will be. It still comes down to how much to you want all the refinements around you, and what are you willing to pay for it. After having Range Rovers for years, I still think highly of the GX, and look forward to having to take it in very little for service. I do miss the European version of a Luxury Vehicle, but I sleep better at night. :)

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