caha14

Same here... It never bothered me much before the "fix", and now it's even better.

The thing I can't figure out is how Jeep was able to fix it in a fairly simple way (read my post early in this thread), yet Toyota/Lexus keeps jerking people around and offering a band aid for the problem. The clunk in the Jeep was much worse than anything I've felt in the GX, and their fix worked flawlessly. No clunk ever again in the 40k miles I owned the Grand Cherokee.

lonewolf69

Tony, Caha,

Just so that we're on the same page here, were any of the "THUMPS" you've felt ever strong enough to "spill" a cup of coffee (NOT that ANYONE in their right mind would even think about putting food or drink in the GX), but I just wanted some "comfort/re-assurances", as I only had Johnny's experience to bank on (no offense Johnny)...

Thank you ALL in advance!

caha14

Definitely not. Do you know the feeling in some cars when you're stopped, your foot is on the brakes - but not too hard, the A/C compressor kicks on, the engine revs up, and the car moves a little bit? That's how it felt in my GX.

Just for your reference, in the Jeep it felt like someone rear ended you at 1 or 2 mph, but still not strong enough to spill coffee.

And by the way, it's in the owner's manual:

"Your GX470 is equipped with cupholders throughout the cabin. However, these are for ornamental purposes only and not meant to be used. Bringing beverages on board is not recommended by Lexus and may void your warranty."

Tony

No non of the clunks were bad enough to spill anything.

sclx

I just traded in my 1998 LX470 for a 2005 GX (no KDSS) and I have the clunk. I have had that exact same clunk in my LX for 7 years. It's just the self leveling suspension settling. This is why some people are noticing it after freeway driving or various changes in speed - since that is when the suspension may settle. It has never bothered me, and I didn't even think anything of it when it happen at the first stop light after driving away from the dealer. It does not happen every time, but I don't think its a big deal. I have notice it happen more when I'm already stopped and I let off the brake a little. Again, this is because the self leveling suspension only moves when the brakes are not pressed (and when the doors are not open). The suspension in the LX moved up and down a lot more than the GX (front and rear also instead of just rear). It moved a few inches up and a few inches down, so it was very noticeable.

Hopefully this info helps a little?

lepoch

Hi---I have the clunk when I have the suspension turned off, I don't think that is it. A friend thinks the thunk on letup of brake is the hill start assist control letting go. The thunk sorta feels like my last SUV when I had locked the center and rear differentials and was turning---it felt alot like this one, the binding up in the geartrain.

thanks

itsZep

caha14:

Thanks for the info you posted.

Ya know I had a Grand Jeep Cherokee that did the same thing too. (thump at stop)

When my GX started doing it.....I was like ....."wow it must be something about the way I drive".

I feel better now!

I am not mechanical, and did not know this was a design problem.

My GX does it sometimes, but my Cherokee did it alot.

It is kind of a "pain".

Wish they had an easy fix.

=(Zep)=

Johnny Mo

Okay - so I had my service done on the driveshaft...from my perspective the whole thing was more of an annoyance than a real concern. There were times I'd drive for weeks with no thump and other times where I'd get a thump 2-3 times a day (although that was rare too). In any case I figured screw it, it bugs me I'm gonna get it fixed.

As far as what is done - my understanding of it is just a re-lubrication of the drive shaft (or propeller) as it is called in the TSB. They did not replace the actual part, which is what I thought some people had alluded to in earlier posts on this issue.

As far as I can tell the thump is still there, but it is definitely more subdued (not that it was that bad to begin with) Again, for me it was an annoyance not a concern...on a 50k vehicle witht he quality reputation of Lexus you'd expect it not to exist in the first place, or for it to be addressed properly...I don't think this one is going to quite make the fence - long fly ball...it's deep...caught at the warning track.

Sorry for the baseball reference - must've been the fact that the last thing I watched was the Yankee game.

tetra7

This thump reminds me of something that was happening on an Isuzu thread almost 8 years ago. The newly designed Rodeo (back then) had a really annoying thump in the driveline and all the customers complained about it. End result was that they changed the lube to a very heavy, white lithium based product which resolved the issue.

Ntwrks1

I talked to my Lexus dealer service dept manager last week about this - he said they have been replacing driveshafts and that seems to help with the problem, BUT he did inform me that they are supposed to be coming out with a real fix before too long. Possibly next several months. He offered to schedule an appointment for our GX to have the driveshaft replaced, etc. now, but I said that we might as well wait since we have additional time left in our warranty. The truck still has under 15k on it.. boy that clunk really drives my wife and I nuts though.. just annoying. I try so hard not to come to a complete stop, just keep it going like 1/2 mph or so when slowing down for a stop sign, etc..

HoleinOne

I wouldn't hold my breath for the "real fix that may be available in a few months". I was told by a service rep that the official response, as a directive from the Lexus corporate customer service department to all Lexus dealers, is that it is now considered a "normal operational characteristic" of the vehicle. Most dealers will not even spend the time to re-lub the drive shaft since it is a very short term thump minimizer at best.

I am not concern about it as a safty problem. I am more concern about its affect on the vehicle's resale value.

Dlpsev

So I've been following this link concerning this thumping on the Lexus 470 truck.. lots of unhappy people and Miss diagnosis.. here's what I found out.. I have a 2005 Lexus GX470 and experience some of the same symptoms a lot of people are talking about.. this something issue has nothing to do with the drive shaft rear sway bar etc etc.. issue is directly related to the air suspension system and airbags.. after observing this condition for quite a while and beyond frustrated I took matters into my own hands.. I have the same experience as many of you claim it feels like the truck is being hit from the back a thumping feeling at stop.. something while you let off the brake or begin to accelerate and so on.. I haven't solved the problem yet but I know 100% it has nothing to do with the drive shaft or the rear sway bar it's definitely in the air suspension system.. seems like when the car is rising up it goes beyond its high-level point and that's when the thump is experienced.. if you watch closely or listen closely you will see this thumping feeling you experience only occurs while the airbags are raising. I'm putting this out here because there's a lot of people having the same problems and lots of these problems are being misdiagnosed by the dealers.. also if you become completely frustrated and tired of this system my understanding is you can switch over to a coil and shock system they have a retrofit available.. my truck is going back to my mechanic next week for follow up and I will post again once I have a resolution

chiph9

This is a very old thread!

What was found later was that the splines on the propeller shaft (rear driveshaft) were built wrong. I experienced the "thump" when coming to a stop and also the poor shift quality on the 1-2 up-shift (the time when the most torque is being applied). Replacing it with the redesigned part solved the problem. The dealer will have the TSB that has the new part number. Cost is around $700 but many people report being able to negotiate a lower price.

The air suspension system should only adjust the height when commanded to by using the console switch (there are rules about what heights are allowed at what speeds), or when passengers or cargo get added/removed (the system compensates for weight added to the vehicle, either passengers, cargo, or towing). If you take some friends on a trip and you all step out at the same time, you should hear the valve open and release some pressure right around the time you close the doors.

So if you're seeing the height change as you drive, and/or resting on the bump-stops while driving, there's a problem with the air suspension. By far, the most common cause is a leak in one or both bags. But it can also be caused by a bad height sensor reporting the wrong value to the computer. Check the bags first by spraying soapy water on them and looking for bubbles. If one is bad, you might as well replace both since they're the same age. Or like lots of other people have done - swap them out for traditional coils available from 3rd parties (there are lots of other threads about this here).

Chip H.

ALAN553