77 Drive Line Vibration
05-13-2019, 07:08 PM
#1
Advanced
Thread Starter
77 Drive Line Vibration
Ever since I got this car there has been a vibration when driving--I feel it through the steering wheel and shifter lever especially but the whole car has a slight vibration most noticeable when accelerating. Thought it might go away when I had both front and rear suspension rebuilt and new Bilstein HD Shocks but still there. The shop gave it a "thorough" inspection when I first bought the car but I am beginning to think they missed something--maybe the u-joints/ drive and half shafts... Here's the drive line: ZZ1 GM Crate motor, BW Super T10 Trans with new Macleod Pro/Street Clutch, original 3.73 gear. Any thoughts? Bent drive shaft maybe?
05-13-2019, 09:17 PM
#2
Melting Slicks
Since you say its driveline, I assume you've determined its not engine or clutch. The fact that it seems worse under acceleration suggests a driveline problem associated with movement of the differential under acceleration. I would check the differential pinion mount.
The following users liked this post:
LFOTremolo (05-13-2019)
05-14-2019, 11:52 AM
#3
have you tried swapping front and rear wheels?
05-14-2019, 12:47 PM
#4
Race Director
Did you think to check the drive shaft angle when you swapped out the trans?
Did you have to shorten or replace the drive shaft, was it balanced?
Did you have to shorten or replace the drive shaft, was it balanced?
05-14-2019, 05:24 PM
#7
Advanced
Thread Starter
Super T10 is original to the car--been wondering about the shaft angle though--work was done before I got it (engine swap). I guess you need to pull the shaft to see if it is aligned correctly and to check the balance... I'm not a mechanic so I will likely be taking it to where the majority of the recent work was done--trying to get a feel for what the issue(s) may be.
05-14-2019, 07:37 PM
#8
Race Director
Good luck.
The following users liked this post:
LFOTremolo (05-14-2019)
05-15-2019, 04:15 AM
#10
Advanced
Thread Starter
Croaker how much drive train work has been done to your car? Engine or rear end (or both) ever been pulled? Saw on a MT Show recently that a test drive after an initial build had a drive line shimmy that had been corrected with a shaft realignment. My car had originally been reassembled onto a new frame as the old one had rusted out so it's been all apart and back again. Wondering if the original builder had gotten the alignment correct from the get go (or not). I have a buddy with a shop so hopefully he can see if this is the deal (the shafts and u joints look pretty tight).
05-15-2019, 08:51 PM
#11
Melting Slicks
New joints , clutch, rear end was rebuilt before I bought the car. After changing the joints on the axle shafts it got a little better but I dropped the clutch kinda hard and back again. I kind of just started living with it. Maybe when I finish my other project I’ll take another look. I’m learning a lot on my newest project. I don’t know if I like it or hate it at this point.
The following users liked this post:
LFOTremolo (05-16-2019)
05-16-2019, 12:30 AM
#12
Team Owner
If you have old tires (6 or more years old), get those checked out well and balanced (or replaced!) before you do any more diagnosis on your vibration. It could all be in the tires.
Also, when you accelerate to a speed where the vibration is worst, let off gas and push in the clutch (to put engine at idle condition and disconnect engine from drivetrain). See if you have the same level of vibration or if it is noticeably less. Use techniques like this to "pare down" the possible causes.
Also, when you accelerate to a speed where the vibration is worst, let off gas and push in the clutch (to put engine at idle condition and disconnect engine from drivetrain). See if you have the same level of vibration or if it is noticeably less. Use techniques like this to "pare down" the possible causes.
The following 2 users liked this post by 7T1vette:
croaker (05-16-2019),
LFOTremolo (05-16-2019)
05-16-2019, 04:50 AM
#13
Advanced
Thread Starter
If you have old tires (6 or more years old), get those checked out well and balanced (or replaced!) before you do any more diagnosis on your vibration. It could all be in the tires.
Also, when you accelerate to a speed where the vibration is worst, let off gas and push in the clutch (to put engine at idle condition and disconnect engine from drivetrain). See if you have the same level of vibration or if it is noticeably less. Use techniques like this to "pare down" the possible causes.
Also, when you accelerate to a speed where the vibration is worst, let off gas and push in the clutch (to put engine at idle condition and disconnect engine from drivetrain). See if you have the same level of vibration or if it is noticeably less. Use techniques like this to "pare down" the possible causes.
Great ideas--need rear tires and will have the fronts rebalanced--they aren't more than around 5 years old but definitely the best way to eliminate that from the investigation. Thx.