c3 vibration
Thread Starter
3rd Gear
Joined: May 2015
Posts: 3
Likes: 0
c3 vibration
I have a 79 c3. Just completed a complete overhaul of the entire car with the exception of the automatic 350 transmission. New u-joints, professional diff, rebuild, wheel bearings etc. At around 50 miles an hour I start felling a vibration. It never goes away even at higher speeds, however if I shift the car into neutral it goes away immediately. There is very little movement if the tail shaft on the transmission. Any thoughts on what could be driving this?
Drifting
Joined: Aug 2010
Posts: 1,839
Likes: 45
From: nassau co. new york
this topic has been discussed at length in past threads so start there first.i had this issue and it was not only one thing causing it.in order of importance for me was drive line phasing,angle between tranny and differential,u-joints,and old unbalanceable tires.i remember what was said on a vibration checklist that stated vibration is caused more by an imbalance further away from the center of rotation.i hope this helps.
Melting Slicks
Joined: Jun 2011
Posts: 3,114
Likes: 597
I have a 79 c3. Just completed a complete overhaul of the entire car with the exception of the automatic 350 transmission. New u-joints, professional diff, rebuild, wheel bearings etc. At around 50 miles an hour I start felling a vibration. It never goes away even at higher speeds, however if I shift the car into neutral it goes away immediately. There is very little movement if the tail shaft on the transmission. Any thoughts on what could be driving this?
http://www.hurst-drivelines.com/file...ration-FAQ.pdf
While this document covers a 5 or 6 speed manual (tremec) conversion this does cover the steps to help.
If you have another set of tires I would give that a try first. or it may be alignment related ?
When putting the car in netraul did you also keep the same engine RPM ? if not check using the same RPM while in Netrual.
Last edited by cagotzmann; Jun 28, 2015 at 02:42 PM.
Thread Starter
3rd Gear
Joined: May 2015
Posts: 3
Likes: 0
Have a read through this
http://www.hurst-drivelines.com/file...ration-FAQ.pdf
While this document covers a 5 or 6 speed manual (tremec) conversion this does cover the steps to help.
If you have another set of tires I would give that a try first. or it may be alignment related ?
When putting the car in netraul did you also keep the same engine RPM ? if not check using the same RPM while in Netrual.
http://www.hurst-drivelines.com/file...ration-FAQ.pdf
While this document covers a 5 or 6 speed manual (tremec) conversion this does cover the steps to help.
If you have another set of tires I would give that a try first. or it may be alignment related ?
When putting the car in netraul did you also keep the same engine RPM ? if not check using the same RPM while in Netrual.
Yes and no vibration. Thanks for the info.
Thread Starter
3rd Gear
Joined: May 2015
Posts: 3
Likes: 0
this topic has been discussed at length in past threads so start there first.i had this issue and it was not only one thing causing it.in order of importance for me was drive line phasing,angle between tranny and differential,u-joints,and old unbalanceable tires.i remember what was said on a vibration checklist that stated vibration is caused more by an imbalance further away from the center of rotation.i hope this helps.
Thanks for the feedback.
Le Mans Master
Joined: Jul 2006
Posts: 8,117
Likes: 104
From: charlotte north carolina
Check all the U joints for proper installation. It could be a bad joint that only vibrates under load. Then try to localize the problem. If the vibration stops when you put it into neutral (or disengage the clutch and and let the RPMs drop), it's not in the suspension or driveline. They continue to rotate at MPH, not RPM. It's in the engine. Remove the belts to the accessories and test it. If the vibration stops, you know it's in something that was disconnected. reconnect things one at a time and test. If the vibration does not stop, it's internal to the engine.
Le Mans Master
Joined: May 2003
Posts: 8,874
Likes: 3,551
From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
I had a vibration in my 73 at about 3000 RPM- 4th gear...I noticed when I filled the tank up the vibration would go away... Made me think that the extra weight of the gas was changing the driveline angle...
So I used this Tremec App on my I-phone. Then shimmed up the transmission to solve the issue.
App- it's FREE Also has gear ratio MPH & tire size
http://tremec.com/menu.php?m=154
Good article-
http://www.hotrod.com/how-to/additio...le-finder-app/
So I used this Tremec App on my I-phone. Then shimmed up the transmission to solve the issue.
App- it's FREE Also has gear ratio MPH & tire size
http://tremec.com/menu.php?m=154
Good article-
http://www.hotrod.com/how-to/additio...le-finder-app/
