ive got this vibration and i think i need a new driveshaft but i want opinions. here how the story goes: to start. this all is in a 65 coupe 289 C4 8" dropout...
i changed my gears from 2.78 to 3.55 and ever since then ive had a nasty vibration probably around 45-55 mph(speedo says 60-70) its there while accelerating to that mph but not very noticable unless looking for it. then once i hit that mph its nasty for the 10mph range. once i get above it, the vibration is still there but not as quite as bad. the gears have the correct pattern, yoke was marked and installed in correct position. u joints were replaced, wheels balanced. when tranny is in neutral, the vibration is still there so its not in the engine or tranny.
from what i can remember, my car never really liked to go over 80mph. it got pretty nerve racking. i cant remember if it was a vibrations like i have now or what but im thinking it was.
what i can come up with is that the drivehshaft is and always has been out of balance and i never noticed it before because it never spun as fast as it does now because of the gear ratio change.
i changed my gears from 2.78 to 3.55 and ever since then ive had a nasty vibration probably around 45-55 mph(speedo says 60-70) its there while accelerating to that mph but not very noticable unless looking for it. then once i hit that mph its nasty for the 10mph range. once i get above it, the vibration is still there but not as quite as bad. the gears have the correct pattern, yoke was marked and installed in correct position. u joints were replaced, wheels balanced. when tranny is in neutral, the vibration is still there so its not in the engine or tranny.
from what i can remember, my car never really liked to go over 80mph. it got pretty nerve racking. i cant remember if it was a vibrations like i have now or what but im thinking it was.
what i can come up with is that the drivehshaft is and always has been out of balance and i never noticed it before because it never spun as fast as it does now because of the gear ratio change.