i am a owner of a 95 lexus sc300, and i am having the same issues with vibrations in the drivetran. the vibration only happends at about 5mph. then after 5mph it goes away... then when i am coming to a stop, it starts to vibrate again at 5mph untill i come to a complete stop. i have other friends with lexus sc300s and toyota supras that had the same issues in the past. they told me it was the center support bearing, or the carrier bearing on the driveshaft.
ive yet to figure it out on my car, i am going to put it up on jack stands and check the under the car today. i will keep you guys updated
if anybody has had these issues before, please let me know on what could it be.
thanks