Help with vibration????
Thread Starter
Burning Brakes
Joined: Jul 2006
Posts: 826
Likes: 22
From: Chicago Area
Help with vibration????
Hi all,
69 4 speed car. I have a pretty noticeable vibration that comes in at about 55-60 mph and is really only noticeable under load (accel or decel) and then about 80ish it will somewhat fade out but it's still there. Just cruising it;s not so bad but I step in it at all I feel it. Where would I begin? Definitely feels like driveline. U joints? what do I look for if I get under there?
Thanks!
69 4 speed car. I have a pretty noticeable vibration that comes in at about 55-60 mph and is really only noticeable under load (accel or decel) and then about 80ish it will somewhat fade out but it's still there. Just cruising it;s not so bad but I step in it at all I feel it. Where would I begin? Definitely feels like driveline. U joints? what do I look for if I get under there?
Thanks!
Thread Starter
Burning Brakes
Joined: Jul 2006
Posts: 826
Likes: 22
From: Chicago Area
Will do. Not too many miles since a frame off, but ya never know. I did notice that the drivers rear wheel is a bit on a angle compared to the passenger. I have seen this on C3's before. It's not severe and the car drives straight as an arrow. But I did notice it the other day when I was looking from behind it...
Melting Slicks
Joined: Jul 2010
Posts: 2,503
Likes: 33
From: McGrady NC
St. Jude Donor '15-'16
I've read somewhere on the forum about drive line vibrations in the earlier C3's. It seems like the drive shaft needed to be balanced or was out of phase (slightly off relationship angles between the transmission and differential). A forum search for the might be helpful. 
Thread Starter
Burning Brakes
Joined: Jul 2006
Posts: 826
Likes: 22
From: Chicago Area
I've read somewhere on the forum about drive line vibrations in the earlier C3's. It seems like the drive shaft needed to be balanced or was out of phase (slightly off relationship angles between the transmission and differential). A forum search for the might be helpful.
Melting Slicks
Joined: Jul 2010
Posts: 2,503
Likes: 33
From: McGrady NC
St. Jude Donor '15-'16
I would say drive shaft first. The length of it and the rotational speed compared to the half shafts would create the harmonics you are experiencing. Half shafts turn slower and the vibration would be more isolated unless you had a bad or misaligned u-joint.
Advanced
Joined: May 2013
Posts: 66
Likes: 0
From: Olathe KS
I had a similar problem in my old camaro. It ended up being the U-Joints. Not sure if that will translate to a C3 corvette but your description of the issue sounds exactly the same. It happened near my shift points when accelerating and de-accelerating.
Thread Starter
Burning Brakes
Joined: Jul 2006
Posts: 826
Likes: 22
From: Chicago Area
Yeah pretty much the same here. Drives me nuts sometimes...and whats strange is it seems to be worse at times. No idea why....
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Thread Starter
Burning Brakes
Joined: Jul 2006
Posts: 826
Likes: 22
From: Chicago Area
Really? What are you thinking yours is now? Well I am planning on a 5 speed for the car this winter so if it is in the trans that will solve that. I know it's not motor. It's only at like 55-70 under acel or decel...and it's still there a bit at say 75-80 but barely...
Thread Starter
Burning Brakes
Joined: Jul 2006
Posts: 826
Likes: 22
From: Chicago Area
Thanks, I will do that. Gotta get it over to my buddys lift hopefully next weekend. Would love to find it because other than that this car is AWESOME to drive!
Racer
Joined: Jan 2009
Posts: 261
Likes: 1
From: frederick maryland
my car had, and still has a vibration issue...heres what ive done
i changed all the u joints right after i purchased my car since i had to drop the rear end anyways to fix a yoke issue. afterwards the vibration was a bit worse. i didnt get the correct rubber mount for the front of the differential with my u joints, so i didnt replace it for the first drive. when the diff mount arrived i changed it and the vibration was noticeably better. i read up here on driveshaft angle & alignment - figured what the heck - ran down to NAPA and grabbed a new rubber tranny mount. pulled the old one, measured both...the new one was 1/8" taller. installed the new one and 80% of my vibration was gone. now theres just a slight vibration when cruisin that passengers in the car dont even feel.
my next step is to install the middle exhaust bracket which was missing when i bought the car. this will lift the tranny another 1/8" or so, and hopefully bring everything into correct alignment
ive done the angle measuring and i knew my tranny needed to come up a bit. i dont remember how to take the measurements though. i found it all here searchin
hth
i changed all the u joints right after i purchased my car since i had to drop the rear end anyways to fix a yoke issue. afterwards the vibration was a bit worse. i didnt get the correct rubber mount for the front of the differential with my u joints, so i didnt replace it for the first drive. when the diff mount arrived i changed it and the vibration was noticeably better. i read up here on driveshaft angle & alignment - figured what the heck - ran down to NAPA and grabbed a new rubber tranny mount. pulled the old one, measured both...the new one was 1/8" taller. installed the new one and 80% of my vibration was gone. now theres just a slight vibration when cruisin that passengers in the car dont even feel.
my next step is to install the middle exhaust bracket which was missing when i bought the car. this will lift the tranny another 1/8" or so, and hopefully bring everything into correct alignment
ive done the angle measuring and i knew my tranny needed to come up a bit. i dont remember how to take the measurements though. i found it all here searchin
hth
Thread Starter
Burning Brakes
Joined: Jul 2006
Posts: 826
Likes: 22
From: Chicago Area
so I'm wondering if from age the traine sits lower on the mount from the age of the mount? I'm assuming angles should be pretty straight going from the trans to the differential....
Burning Brakes
Joined: Nov 2004
Posts: 1,193
Likes: 176
From: Hillsborough NC
I had similar vibration in my driveline as well. The below article does a good job of explaining how to do the alignment. Fixed my issue, which was in the 60-70 MPH range.
http://www.hurst-drivelines.com/file...roc_111606.pdf
http://www.hurst-drivelines.com/file...roc_111606.pdf
Thread Starter
Burning Brakes
Joined: Jul 2006
Posts: 826
Likes: 22
From: Chicago Area
I had similar vibration in my driveline as well. The below article does a good job of explaining how to do the alignment. Fixed my issue, which was in the 60-70 MPH range.
http://www.hurst-drivelines.com/file...roc_111606.pdf
http://www.hurst-drivelines.com/file...roc_111606.pdf
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
my car had, and still has a vibration issue...heres what ive done
i changed all the u joints right after i purchased my car since i had to drop the rear end anyways to fix a yoke issue. afterwards the vibration was a bit worse. i didnt get the correct rubber mount for the front of the differential with my u joints, so i didnt replace it for the first drive. when the diff mount arrived i changed it and the vibration was noticeably better. i read up here on driveshaft angle & alignment - figured what the heck - ran down to NAPA and grabbed a new rubber tranny mount. pulled the old one, measured both...the new one was 1/8" taller. installed the new one and 80% of my vibration was gone. now theres just a slight vibration when cruisin that passengers in the car dont even feel.
my next step is to install the middle exhaust bracket which was missing when i bought the car. this will lift the tranny another 1/8" or so, and hopefully bring everything into correct alignment
ive done the angle measuring and i knew my tranny needed to come up a bit. i dont remember how to take the measurements though. i found it all here searchin
hth
i changed all the u joints right after i purchased my car since i had to drop the rear end anyways to fix a yoke issue. afterwards the vibration was a bit worse. i didnt get the correct rubber mount for the front of the differential with my u joints, so i didnt replace it for the first drive. when the diff mount arrived i changed it and the vibration was noticeably better. i read up here on driveshaft angle & alignment - figured what the heck - ran down to NAPA and grabbed a new rubber tranny mount. pulled the old one, measured both...the new one was 1/8" taller. installed the new one and 80% of my vibration was gone. now theres just a slight vibration when cruisin that passengers in the car dont even feel.
my next step is to install the middle exhaust bracket which was missing when i bought the car. this will lift the tranny another 1/8" or so, and hopefully bring everything into correct alignment
ive done the angle measuring and i knew my tranny needed to come up a bit. i dont remember how to take the measurements though. i found it all here searchin
hth
Thread Starter
Burning Brakes
Joined: Jul 2006
Posts: 826
Likes: 22
From: Chicago Area
I have brand new hoops on it (BFG Radial TA's) and when I coast or maintain speed it's smooth as butter. It only accel or decel and at higher speed, so I know it's in the drive line somewhere....