O.k. here is the rundown. I have a vibration when driving in my 1992 sc300. It doesnt show up until you get to 55mph and then it comes and goes depending on how you are driving the car.
The vibration gets really bad soemtimes to where the entire car is shaking. I have balanced the wheels and checked all the suspension components that I can think of and to no avail. Any insight into this could be helpful.

 

Could be: Control arm bushings (especially lower), motor mounts, tranny mount, few other things

 

I am pretty sure the lower control arm bushings are o.k. I had the characteristic clunking noise when going over bumps so I replaced them about a year ago. This vibration seems like something else because I can feel the vibration strong in the steering wheel, pedals, seats, floor etc... Even the auto shifter handle gets to floppin around when the car is shaking.

 

then i dropped 500 for new tires. most likely its your tires. my car was the same. i couldn't go fifty or above because of the seizures my car was having.

 

probably your driveshaft is causing it, check the guibos and the center support.

 

I have tried it with different wheels and tires and the vibration is still there. I am going to check my mounts as soon as I can. I know I had heard os a driveshaft bearing causing vibrations, does anyone know if my symptoms could point towards that? Anything in particular to look at with my mounts?

 

What are the guibos?

 

the rubber bushings between the driveshaft and differential

 

I will check those, is there anything in particular for me to look for?

 

what i suggest you do is, put the car on a lift, and have someone put the car in gear, and look for any driveshaft vibration.

 

Hay ! are you using hub rings adapters with your wheel?

 

No hub ring adapters, I am going to put it on my lift tommorrow and see what I can find out

 

I see you got 20" wheels. You should get a set of hub adapters they a stremely sheap and could
be the solution to your problem. " I run a car audio & accesories shop and I see that every day. People complain about bivebration and 9 times out 10 that takes care of the problem."

 

 

I experienced similar characteristics when I first bought my SC - shaking above 50 mph. It turned out that one of my brake calipers were 'stuck'. When you have your car up on the lift, try rotating each wheel by hand.