vibration; 99 LS400

[Abe Scott]

I have 99 ls400 base, that has a vibration. the engine has been swapped, engine and trans were pulled and installed as a unit. after swap the vibration started mild. now I don't drive it much because of the vibration. the motor mounds were replaced. at idle it doesn't vibrate, only when driving is it possible the drive shaft was installed back or the saddle bearing needs to be replaced. I replaced the torque converter bolts hoping that was it. any ideas is appreciated 

 

[Bykfixer]

If you run the engine at say 2000 rpms with it in park does it vibrate? 

If the needle bearings are going bad you normally hear a "clunk" noise when putting it in drive or reverse. 

Wheel out of balance? 

 

[Abe Scott]

This may a possibility. I would thank that if it is a tire, I should have notice it before engine swap. And it may be, or I am I just trying to make a mountain out of a mole hill. thank you very much.

 

[paulo57509]

It's either driveline or wheels/tires.

At what speed (engine/road) does the vibration occur?

Does the vibration change when you're on the throttle or off or no change?

Try swapping the spare at each corner to see if the vibration changes.

[Abe Scott]

the vibration started at 55 and gone down ever since. thanks for question because speed for vibration is always lower it more than likely the drive train. any will check it out . when I get over surgery

 

[Ian Huang]

Check out this article

[Abe Scott]

Thank you for your input I was thinking the drive shaft. I had not considered the transmission mount it is still a few days until I and get under the vehicle. thank again I see this conversation took place in 2009 

 

 

[Abe Scott]

I had sometime to get under my LS and replaced the trans mount no more vibration. Thanks again for the input.