lexusonly1

hello all
i have a lexus LS430 2002 and am looking for a soltion to a problem i am facing, and hoping to find one.
when i push the accelerator while the car is in moving position i hear some strange noise as if metals are grinding. the same doesnt happen when I push accelerator and the car is in still position.

let me explain the noise with an example, when driving a manual transmission vehicle 20MPH and change the gear to 4th or 5th, there is a sound that comes out,[krrrrrrrr] im having similar noise but bit low.

this noise is very apparent when the vehicle is atapproximately at 40 MPH and a i push the accelarate hard OR when the vehicle is approximately at 100MPH and i shift the gear from D to 4th.

hope the question is clear, looking forward to comments from you guys
thanks in advence

ancdmd

how many miles on the car? Try recording the noise with the video function on your phone if you have one and uploading to youtube then post the link...

lexusonly1

thanks for reply...miles obove of 120k..i tried to record the noise but it is low & can`t be recorded.
Do you have any suggestion on where and how the noise is coming?

lexusonly1

102 viewers n only 1 reply....guys plz help!!!

Jabberwock

Given the millage suggest you check motor mounts - excessive engine movement may be causing something to touch and rub or grind.

ancdmd

Motor mounts likely need to be replaced and also can cause a myriad of noise issues. My 2002 with 133k miles had two broken motor mounts which went undiagnosed by six techs in the last year. My noise problems were almost completely eliminated by installing new motor mounts and a new driveshaft bearing. However the noise in the first video of the thread below is still just barely audible (its so slight that even I can barely detect it, but I lived with it being so loud for so long that I think I even hear it in my sleep), so I know its something else, but it sure was exacerbated by the bad mounts. I'd say given the age and mileage of your car it is definitely wise to have the mounts replaced along with the transmission mount, then go from there. If they're not completely bad by now they will be soon. See my recent thread:

https://www.clublexus.com/forums/ls4...ses-audio.html

ancdmd

I'd almost bet $100 that your driveshaft center support bearing is bad. When mine went bad it made a low grumbling sound like metal gear chatter or bad wheel bearing. It then progressed to an awful louder whining sound. It makes sense because your symptom only occurs with the vehicle in motion and is independent of engine speed. If the motor mounts are bad this noise can be exacerbated.

lexusonly1

thanks for reply....will check motor mounts today

lexusonly1

thanks bro for your detailed reply...will check motor and transmission mounts by tech...
about the noise in your 1st clip it is from driveshaft, the nut between them [near to driveshaft center support bearing] is loosed try to tight it and that noise will 100% gone.
I had the same problem and now went away by tighting the nut between the driveshaft.

ancdmd

Are you talking about the nuts and bolts on the flange at the front of the driveshaft where it mounts to the transmission output shaft? The ones the go through the round rubber vibration damper?

lexusonly1

no bro im not talking about these nuts and bolts. it is only one nut and you can see it after removing the alumunium sheild over the exhaust.

part number 37328-50010 [ NUT, PROPELLER SHAFT ADJUSTING ]
go to :www.t o y o d i y.com without space and enter the part number...hope this will help you

ancdmd

Ok I know which nut it is now. I just had the center support bearing replaced a month ago, I wonder if that nut loosened up a bit since then, since that noise is still slightly detectable. I'm pretty sure the tech didn't remove the front shaft from the car to replace the bearing, just the rear shaft. I'm not sure if this nut was even touched. I'll have it checked at my next oil change.

lexusonly1

i`ve replaced motor mounts both were totaly broken.however the noise is still audible. it is like the noise in your 1st clip but yours is constant and mine is sometime. should i change driveshaft center support bearing ??
transmission mount was ok i have replaced it 4 months ago

HMattinson

Same noise on my IS250 (KRRRRRup)

Lexusmama

My car as well is making a grinding tire sound when driving then it will stop I don;t know what it could be I have a Ls400 94