rhythmic vibration on hiway

-
7

72golddustermike

Well-Known Member
Joined
Oct 13, 2010
Messages
436
Reaction score
71
Location
northeast arkansas
need some help here. diving car at 55 plus i have a rhythmic hum or vibration.it only does it with foot on accelrator if you let of it stops.i took drive shaft out u joints look good replaced during build of car about 3 mnths ago.i even swapped shafts with dads dart sport still same.got new wheel vintiques 15 inc ralleys and bf goodrich tires from summit. i also have slight howl when let of accelrator. any ideas what this could be?
 
72golddustermike said:
need some help here. diving car at 55 plus i have a rhythmic hum or vibration.it only does it with foot on accelrator if you let of it stops.i took drive shaft out u joints look good replaced during build of car about 3 mnths ago.i even swapped shafts with dads dart sport still same.got new wheel vintiques 15 inc ralleys and bf goodrich tires from summit. i also have slight howl when let of accelrator. any ideas what this could be?
Click to expand...
do you have the "c" clips on the ujoints that center the ujoint on the yoke??? I didnt and man I had a bad vibe, just a thought..
 
What rear are you running? Have you checked your pinion angle? Is your rear yoke loose?
 
Does the vibration have the frequency of a heard of pissed off bumble bees? If so, that's classic driveline vibration.
 
Yup. You cannot check a shaft without pulling it out. Remove the two rear caps and inspect for grease. "Easily" move the other two bearings, feeling for "smooth movement" should not fee dry or "crunchy" or overly tight

Now wiggle front joint in every possible way, same thing.

Check pinion bearing/ drive yoke for looseness. Rotate rear yoke back, forth, feeling for excessive play/ wear, and side looseness. Don't discount rear may just be low on lube

You may be developing serious ring/ pinion wear problems.
 
I'm having the same problem myself, after 55mph it starts to vibrate the car and you can feel it in your butt. My U joints are 2 months old. Maybe the driveshaft needs a balancing?
 
well took wheels and got them checked for balance they were not even thoght summit was supposed to balance them.i am runnig 8.25 rear with 3:55 surigrip. im gonna put wheels back on and see if that helps if not ill check pinion angle with magnetic angle finder
 
Oscillation.... I'm thinking driveshaft. I'd pull the whole thing and take the entire assembly in to have it balanced before it tears up something more expensive.

My $0.02
 
took a magnetic angle finder put on rear of tranny got a meaurement of87.5 then at rear i got 86.5 if i understand these measurements then i need to us shims to get rear angle more than tranny ? any thoughts
 
:thumbup:turns out preveios owner shortened drive shaft and it was not phased right and was no balanced any way new d-shaft 260$ later fixed it
 
Then that wasn't a rythmic vibration if the weld yokes were out of phase...

That was a intense vibration that got worse with speed.

Also doesn't explain why with another shaft from someone else's
i even swapped shafts with dads dart sport still same.
Click to expand...
car had NO change. . . .
 
You must log in or register to reply here.
-

Back
Top