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

I think you'll find that this noise is normal. The GX470 uses a Torsen center differential as part of the AWD system. Torsen is a natural limited slip unit that uses a very high angle and complicated gear arrangement that tends to hum as you described. It would also be affected by temperature. This is the main reason the the excellent Torsen design is not more widely used. GM used it on the Camero SS and I think Audi still uses it. If the GX470 wasn't so quiet, you wouldn't hear it. It was quite loud in my Camaro SS but so was the exhaust!

my car was having the same noise for a long time, i brought to the dealer 4 times but they didn't identify the problem. i finally fixed it my self, what happened was the cross bar on the roof was loosing real bad and i tight it up and problem went away. hope that the same problem you have

I will check the crossbar on the roof. I assume you mean on the luggage rack?

Greg


I just got my gx-470 full option. I cannot hear the noise,but im curious, does the kdss comes with an on off switch???

I've driven my 2004 Gx from Milwaukee to phoenix and back, and never experienced that noise he described. It can't be normal.

Did you find a fix for this yet? We just bought a 2005 gx470 with the exact same problem and it does seem to be worse when it is colder outside.

HI,I HAD SIMILAR PROBLEM.I GOT IT FIXED.THEIR IS AS TSB ISSUED BY LEXUS FOR THIS PROBLEM WHICH I FOUND ON LEXUS FORUM.UNFORTUNATELT I COULD NOT LOCATE IT NOW.I GAVE WHOLE PRINTED DOCUMENT TO MY DEALER TO FIX IT.I WILL LOOK FOR YOU AND POST IT ASAP.

Im sure this is the fix to your problem--print out and take to your dealer if they want to play stupid.

Humming Fix


AND go read this thread as it talkes about it as well Engine noise

got mine fix under TSIB # DL001-08 FOR DRIVELINE VIBRATION/DRONE
BETWEEN 55 - 75 MPH

What year is your car ?

05

i dono if i have problem , i do feel vibration , but no noise , do you think i have this problem ?????i got 2006 GX with 49000 miles on it

take it to the dealer and give them the tsib# and ask them to check it out.