Ive got a constant vibration. I just got the tires balanced and that really didnt do much. Its constant even in N (while driving) not while parked. I know there rotors are pretty bad so i was wondering if anyone of rotors causing vibes. Of course besides when braking. I dont really feel like the vibes shake the gear shift **** or the wheel more than they should normally. So at this point im ruling out trans or motor mounts. It just feels like i can feel the road. Maybe really bad shocks?

 

get the wheels rebalanced on a proper hunter/road force machine. our cars are by nature very sensitive to wheel balance.

then start looking for play in the suspension.

 

My bet its your u joints.

 

Well, the drive shaft doesnt spin in N so it shouldnt be those. This vibs at all times.

Also, the vibs feels to be felt though the seat and what not the most.

 

I think not. If the car is moving the drive shaft is turning regardless of what gear you are in or if you are in neutral or whatever. The drive shaft is connected to the differential after the tranny.

 

Well, your brake rotors need to be turned or changed anyway, so fix that problem first.

 

Ah true. I forgot about that.

 

Anyone know how to check the U-joint?

 

first step get under and see if there is any play. If there is it is shot. Second step, If there is no play remove the drive shaft and make sure they pivot easily, If they don't pivot easily replace them.

 

Is this an SC or an LS? Check the center carrier bearing on the propeller shaft. Any noise going along with the vibration? What frequency is the vibration? What year and how many miles?

 

LS 99 156k, No real noise that i can hear, It feels like a balance issue but really no vibes in the wheel. You can feel them in the seat.

 

I prolly should have had the tires rotated when i got them balanced.

 

It has to be a balance issue. Who does road force balancing?

 

Go to Hunter's website and do a search for a GSP9700 machine near you...

http://www.gsp9700.com/pub/search/findgsp9700.cfm

 

I have some(times)a more pronounced humming than vibrating sound emanating from the front pass side at certain speed and I just had my tires rotated, both rear tires (almost new treads) moved to front and matching brand new tires (balanced on a hunter machine) installed to the rear. After reading this thread and saw the link, I found a few shops and called the one which is 2 blocks away...needless to say, I am having both front (since I'm not sure if it's balanced correctly) tires balanced and do a Hunter GSP9700 straight track measurement, and check the alignment as well...bought this 99 LS w/ 197K almost 4 weeks ago and it's a one owner (corporate car) with 5 pages of service history from our local Lexus dealer. Hope this eliminates that annoying hum on certain speed.