86' poopra i swapped a sc300 2jzge and r154 with 3.91 lsd into it and i had the 2 piece DS balanced and i have a ford ranger carrier cuz the yoter one shit the bed. anyways there are high frequency vibrations at highway speeds. i cannot make out what is behind me in the rearview mirror it shakes so bad. so i bought a 1piece steel with deading materal inside. guess what i still have vibrations. i asked my old man and he started ranting about flywheels,fans and transmission angles and differential pitch. so please school me on the physics of power transmission without having vibrations