3GSShoe

*SOLVED*

Hi all,

I'm new to this forum. I recently acquired a the 2006 3GS AWD with 170K miles which has suffered severe vibration problems. The car is all stock and kept in immaculate condition. Not dropped and still on factory rims.

The car has received the recall service performed back in 2012 for intermittent misfire and recently received a top engine clean service by Lexus. I have new OEM spark plugs installed. The vibration cut back slightly after the top engine clean but was still pronounced and, I complained, another tech said to perform a top engine clean. When I interjected that this service was just performed 2 months prior, he said well to change the motor and tranny mounts.

Symptoms:
The car has minimal vibration while in park at idle, but the vibration is most severe when I am in the drive gear while stationary (at a light). The second I let off the gas to let the car roll on its own, the vibration ceases. Driving normally at any speeds has zero vibration. If I put the car into neutral, the vibration is minimized even less so than when it's in park at idle.

Diagnosis:
I've had my foot on the brake while I shift from park to Drive, to Reverse, to Neutral without any seeing the engine torquing which led me to think that the 2 mounts are still good. I can't confirm the tranny mount however.


Comment:
I've scoured and read a few dozen threads about vibration problems and most people have it because of dropping their vehicle and CV axle issues. One person mentioned that changing the engine mounts helped minimized the vibration. I've looked after this car since it was first rolled off the lot in 2005 and so I remembered its smoothness and quietness all around in its glory days. I'm considering changing the all 3 mounts myself but wanted advice first if anyone has any other input. Is anyone a quasi-mechanic like me on this forum?

iGS430

Did you change gasoline grade/or gas station?

3GSShoe

Nope. Always use premium gas. Primarily Shell V-power. I don't think changing gasoline would matter considering vibration is minimal while the car is in park or when the car is moving.

The vibration is so severe im afraid it'll wear off all of the sound dampening material inside the car especially around the dash area. My car isn't a rattlebox, YET, but I'm afraid it'll be soon. Not sure what else to do. I'll keep everyone updated after changing the mounts.

ibidu1

iTrader: (1)

Many have said its the torque convertor in our cars. You can try replacing the transmission mount as that should be fairly cheap to replace compared to the if im not mistaken hydraulic filled motor mounts.

3GSShoe

Do you guys know if the motor mounts and tranny mounts are the same for RWD and AWD trims? I checked on Rockauto and it only shows the mounts for RWD trims only.

ServerTech

No, they are not the same. The AWD transmission mount is round, more like a motor mount.

..

3GSShoe

I can't seem to find the correct part number for the motor mounts and tranny mounts. The FSM doesn't list these numbers either.

ServerTech

2006 GS300 AWD parts:
Use your VIN number to get the correct part.
..

dfkd

Transmission fluid change reduced my idle vibration a lot.
And I mean A LOT.

Has yours been replaced?

I did a single drain/fill (3 quarts) and the difference was immediate and got even better with time.

sprtn131

I too have this exact problem... curious if you found a fix? Mine is only noticeable in the first 5 min. When the engine is cold. I first noticed about a year ago... it seemed to have gone away after I replaced a gasket on my exhaust, but now it's back with a vengeance

Gs3500

Does it still happen when car is warmed up?

3GSShoe

sorry I haven't been able to do any work on the car. I promise to report back after tranny fluid change and then maybe a mount change. Fluid was changed about 70k miles ago.

sprtn131

it does not

3GSShoe

Two tranny fluid drain-and-refill 3.1qt's each and no improvement at all. Not sure what to do now other than tranny mounts.

3GSShoe

So:

1. Tranny fluid drain-refill,
2. Changed both new front CV axles
3. New tranny mount (I can see the tranny bouncing up and down during shifting from park to in gear which the mechanic said the mount was broken. I replaced it with OEM tranny mounts and another mechanic said it was broken after 2 weeks replacment. On a lift, I could see the tranny lunging up and down also).

The problem is still persistent with no alleviation whether the engine is hot or cold.

Motor mount would take $1k in labor. Wanted to check if any coils was bad but it would have thrown a code?

I'm out of options.