gswilder

Hoping some of the folks here may be able to help.

I have a 2006 GX470 with KDSS and less than 6,000 miles. It has had an unidentified interior noise (UIN) since I received the vehicle new in November.

It is a "hmm hmm hmm" sound. (kind of like a vibrating washing machine sound) It only happens in the 65-75MPH range. And only when giving it gas. Let off the gas, sound goes away. Give it gas, it comes back. It is pretty loud, as you can hear it over the radio. You get about 2 "hmm" beats per second. Frequency doesn't change depending on speed or RPM. Sounds like it is coming from the middle to rear of the vehicle, but not 100% sure.

It is louder when it is cold outside (30 degrees). But it never goes away even when the vehicle warms up. I have driven it 200 miles at a stretch, and the sound never goes away.

If I shift from D to 4, it goes away.

I have taken it to the Lexus dealership twice and they can find nothing wrong with it. So I am wondering if anyone else here has a 470 with a similar issue?

Any advice that I might be able to take back to my dealer would be appreciated.

Thanks
Greg

GXPrado

Just a guess but maybe harmonic vibration from the driveshaft at that speed. Could ask them to lube/check the DS and make sure it is weighted/balanced correctly.... also make sure the anti-vib weight is on tranny... just throwing out ideas, no idea if any will hit.

Good luck

wbh3

I'm glad someone else has this noise/problem. I haven't seen any other posts pertaining to this, and I'm scheduled for the 10,000 service on Monday. I also have a 2006 with KDSS and get the same noise at the same speed, etc., but it seems to originate on the left (drivers) side of the vehicle. I'm a private pilot/multiengine rated and it sounds exactly as though I'm flying along with one engine at a slightly different RPM, thus that out-of-synch "rummm-rummm-rummm (or hummm, depending on how good your hearing is). Does that help anyone out there diagnose it? Thanks.

GXPrado

The only other thing I can think of off the top of my head is the body mounts. Have them check the body mounts...

gswilder

I cannot tell exactly where the sound is coming from. But I think it is transmission or drive train related. I don't think it is coming from the engine compartment. Especially since it doesn't change with engine RPM.

Any other suggestions would be appreciated. Thanks....

Greg

GXPrado

Greg,
No one here is going to know anything about this. Post a question at toyota120.com or post a question in "chit-chat" on ih8mud.com forums. That will give you plenty of things to look at.

wlee69

Greg - Do you get anymore answers to your question? I don't think it has anything to do with the KDSS as I have a 03 with about 12K miles on it and it does exactly the same thing. Its new to me for about 3 weeks now, and its driving me nuts on the highway.

I'm thinking of taking it in for a look - but before I do that I didn't know if there was a TSB out there or anything....

Thanks,
Will

177mph

Guys - use the search function on this site. This type of noise has been mentioned countless times on this site. It was one of the main complaints of the GX470's since they were introduced in 2003. All GX's have this noise/vibration - most users just dont notice it. It comes thru the steering wheel and gas pedal mostly. It's thought to be a harmonic vibration from the driveshaft/transfer case and lexus has no cure for it. Its not body mounts - or choice of tires - or wheels out of balance. This vibration is only noticed when the truck is at speed in top gear around 1700 rpm - and you must be slightly on the gas.

gswilder

Thanks for the reply. (must have not done a good search) You pretty much nailed my issue exactly. Right down to having to slightly give it gas. I noticed that too. A little more acceleration and it goes away. That is why it drives me crazy on the interstate. 70MPH and slight gas for acceleration. I also noticed the vibration in the gas pedal.

Seems to be a same that Lexus GX470 has had this issue for 2-3 model years and still not corrected. I mean this is a $50K vehicle. What a shame.....

Thanks all.....

peterGX470

I thought the GX have drive-by-wire gas paddle.. No cable, so there should not be any virbration

Everyone is guessing, no one really know what the problem is or where it coming from

177mph

I think Lexus knows - but it would be an expensive fix. I dont think the vibes come from the cable (or lack of one). Its a driveline issue. Transfer case, driveshaft, etc.

The G Man

This may sound stupid, but I had the same problem. I adjusted the front crossbar of the roof rack back about 6 inches and the noise decrease. Also it is now a constant noise, no longer a noise that would hum for 2 seconds and goes away for 1 second and just keep repeating itself. It only happens between 60 to 70 MPH.

Good Luck

177mph

Interesting thought. I have the feeling that the crossbar would make that noise if you were on the gas or not - so that would eliminate it from the choices... Hey - ya never know..

The G Man

Yeah I know, thats why I started the post with " This may sound stupid".

no1sportz

Actually Lexus has issued a TSB for this exact issue. As someone mentioned above is has to do with a harmonic distortion with the front differential mounts. You should be able to get a list of TSBs for the GX470 from your local dealer. It will include the parts list needed for this fix. They may not want to fix it but they have to! Press them and don't let up. The 4Runner (brother to the GX) has the exact issue since they are mechanical twins. Unfortunately Toyota owners have no hope since Toyota is only addressing the Lexus fix. You are lucky!