Harmonic Vibration Rear End ?
Thread Starter
Racer
Joined: Jun 2005
Posts: 305
Likes: 0
From: Oak View Ca
Harmonic Vibration Rear End ?
1999 FRC with new Z0-6 brake system. Just bought the car and it seems to have a harmonic vibration at about 55MPH coming from the rear end. If I swerve to the left it goes away and if I swerve to the right it stays constant. Going straight it comes and goes. Has any one had this and resolved it? What should I look for?
Last edited by Pentacle One; Jul 1, 2005 at 01:40 AM. Reason: quick reply
Le Mans Master
Joined: Dec 2003
Posts: 5,561
Likes: 448
From: Atlanta metro Ga.
From your description it might be a bad wheel bearing. They will make more noise when loaded in one direction or the other.. Also could be the differential plates chattering. Maybe try to change the fluids / make sure you have enough limited slip additive? Hope it isn't serious.. Do you know the history of the car? 
Safety Car
Joined: Jan 2005
Posts: 3,896
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From: Manchester - Political correctness is tyranny with manners.
Originally Posted by Dan_the_C5_Man
From your description it might be a bad wheel bearing. They will make more noise when loaded in one direction or the other.. Also could be the differential plates chattering. Maybe try to change the fluids / make sure you have enough limited slip additive? Hope it isn't serious.. Do you know the history of the car?
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
There is also a harmonic counter balance weight that suppose to be attached to the rear of the DIFFERENTAL! It looks like a round cylinder on a stick! 
I cant rember if it is on the left or right side of the diff. 
Some people remove it not knowing what it is for. See if yours is in place.Bill C
Le Mans Master
Joined: Dec 2003
Posts: 5,561
Likes: 448
From: Atlanta metro Ga.
"There is also a harmonic counter balance weight that suppose to be attached to the rear of the DIFFERENTAL! It looks like a round cylinder on a stick! I cant rember if it is on the left or right side of the diff. Some people remove it not knowing what it is for. See if yours is in place."
FWIW, I tossed mine during my gear swap (and I knew what it was for), in favor of weight savings.. Cannot tell any difference whatsoever.
FWIW, I tossed mine during my gear swap (and I knew what it was for), in favor of weight savings.. Cannot tell any difference whatsoever.
