I have a 99' RX300 AWD, and when I come to a stop at a traffic light, I experience a low droning vibrating noise in the cabin, not so heavy but enough for it to rattle lightly in certain parts of the front interior cabin. Sometimes it can be annoying to the ear, when I drop it in neutral the sound goes away, to the point my ears feel relieved. There is no check engine light or no indicators lit up in the dash. I feel no vibrations through the steering wheel, gear shift, and foot pedals And when I accellerate the pick up is smooth as silk without hesitation, and actually quiet again. Checked the factory muffler and sounds quiet with no holes to be found. Only when I come to a stop while it's in any gear, except neutral. Also the rpm seem to be idling fine. Has anybody else experienced this matter? And what can I do to remedy the issue?

 

check your front engine mount as in the picture. There is also an upper "dog bone" engine mount by the cruise control. Sounds like the engine is rolling forward and both engine mounts are worn.

 

Good looking out, I will definitely check that 1st thing Monday, I have about 158,000 kms is this normal at this point? And can I diagnose this just looking at the condition of the mounts?

 

It is easy to inspect the upper dog bone engine mount, if it is worn, the hard rubber will have cracks, pieces gone. Step on the brake, pop the hood and have another person looking at the engine when you shift from P to R to D, if the engine is rocking around, you got worn engine mounts.
Worn upper engine mount is an idication that the lower one might be worn also since it has to take all that beating. The picture is posted by a member from his Camry but the RX is very similiar.

 

I will most likely check that out tonight, my mechanic ran a full diagnostic check and everything is clean codes, so most likely it's a bolt on replacement(mounts). Thanks again.....

 

Mine has same issue. 2001 with 94K miles. When in N or P, very quite, rpm about 2nd mark. If shift to D with break, vibrates and rpm drops to half between 1st & 2nd mark.

 

I get the same drone with my '02. I sometimes even get a rattle from the Lexus rear plastic license frame rattling against the hatch door. It's not too bad during the warmer weather, but once the temp drops below 20 degrees, it gets worse.

 

After every oil change, inspect the front engine mount to make sure there's no used motor oil on it. Insist that the mechanic wipe it clean. Rubber can deterioate when exposed to dirty oil.

 

Bercasio - did this correct your vibration? I picked up the same vibration after turning 60K miles and I've had the dealer check the vehicle six ways to Sunday. I now just put it in neutral when I'm at a light for a while but I'd like to fix it if I can.

Feedback appreciated.

 

You know I had people on this thread advise that maybe it's the engine mounts, also the Lexus mechanic was bending over backwards trying to figure it out as he notes the engine mounts are in perfect condition, he also checked all the other mounts along the whole drivetrain. We spent hours after closing, looking for the problem and no go. He feels it has something to do with the AWD system maybe causing the vibration when at a stop, as all for wheels wants to move foward. I also do the same thing putting it at neutral when I am @ a light, it relaxes the ears you know what I mean? I see you are from Cali, as I was thinking it only happens when it's cold, i guess that's not the issue. But as of lately the vibrations is starting to calm down allot, still a bit noticable, kinda wierd if you ask me. Is yours AWD? or just FWD? Either way I am just curious as to how this happens?

 

If it doesn't vibrate badly when in neutral, then it isn't the motor mount. The motor mount would consistently transfer vibration to the cabin if it were bad.

It does seem odd that it goes away when in neutral. That might indicate a transmission issue. I'm not exactly sure what the cause might be.

And yes, we have this problem as well. It's a bit annoying, but nothing terrible. Curious to see if anyone ever figures this out....

 

If that front motor mount was having issues, you would also start to hear some unpleasant sounds.

 

Ours is AWD with LSD. Our annoying vibration does not happen all the time either but it definitley goes away completely when I shift to neutral or park. This fact led me to believe that it wasn't the motor mounts and that's why I was curious to see your results.

 

what about the possibility of any loose exhaust components?

 

I have had that issue before with a few components, but it will never make that kind of vibration they describe.