bad vibration over 3000rpm

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midlifecuda

midlifecuda

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Might be a 4 speed issue but many more viewing this forum. 64 cuda with 69 dart gts drivetrain (340 4spd 83/4). I have developed a bad vibration at 3000rpm and higher. It gets much worse when I depress the clutch while driving at these rpms. No noticeable chater/squeal or slipping from clutch. Maybe a little less vibration when first driving cold (hard to tell). At least a couple of thousand miles that I know of without the problem. No noticeble vibration when the back end is of the ground and no movement from the dampner. HELP?
 
midlifecuda said:
Might be a 4 speed issue but many more viewing this forum. 64 cuda with 69 dart gts drivetrain (340 4spd 83/4). I have developed a bad vibration at 3000rpm and higher. It gets much worse when I depress the clutch while driving at these rpms. No noticeable chater/squeal or slipping from clutch. Maybe a little less vibration when first driving cold (hard to tell). At least a couple of thousand miles that I know of without the problem. No noticeble vibration when the back end is of the ground and no movement from the dampner. HELP?
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sounds like a u joint to me. they get sloppy when no load on them like when you push in the clutch or when the back is off the ground. I would start there its the cheapest and easiest..
 
I had something happen like this on my 64 GT Dart when I was much younger. Turned out I forgot to install the C clips on the rear u-joint and I had bolted it up off center.
 
u joints will have a shake under accleration.....at any speed not just 3000 and up....so when you unload the drive train by pressing the clutch in the shake is worse?????Like you are coasting right.....try shutting the car off and coast it...see if it shakes then...may have to rebalance tires.....is it in the seat or steering wheel....seat will be rear tires...steering wheel will be front tires....
 
try jacking up and running it on jack stands and look at drive shaft...see if out round/ which will be out of balance....look at rear tires while it is going around see if out of round...I have changed plenty of tires that have bad run out that will shake...up and down run out...side to side will not shake...may have to put on balancer to see correct run out....bent rim...
 
chasduster said:
u joints will have a shake under accleration.....at any speed not just 3000 and up....so when you unload the drive train by pressing the clutch in the shake is worse?????Like you are coasting right.....try shutting the car off and coast it...see if it shakes then...may have to rebalance tires.....is it in the seat or steering wheel....seat will be rear tires...steering wheel will be front tires....
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Not necessarily, My old Dart was noticeable @ about 3k and up. I'm sure it did vibrate at lower RPM's, it just wasn't as noticeable.
 
I had it up and didn't see anything that looked unballanced, more of a seat/drivetrain issue. Definately dosn't seam like a wheel issue. Waiting for some warm weather and wanted a consenses where to start when it gets here. Don't have alot of time to try and figure this out...lucky I even get chance to take her out!
 
Harmaonic balancer comming apart ?
I had a vibration start suddenly once and found it was a bad fan. Still thankful it didn't throw that loose blade through me. Be careful. Good luck
 
The very first thing you check is both u-joints. Get underneath the car and grap one yoke with one hand and the other yoke with the other hand and see if there is any looseness between them. Also check that the c clamp nuts that hold the rear u-joint caps into the pinion yoke are tight. Checking the u-joints is not something that you can do by just looking at the drive shaft. A vibration in the seat of your pants, especially one that just started, is 95% of the time u-joints. If this doesn't help get all 4 tires balanced and while the rear tires are off check that the brake drum weights haven't flown off.

Terry
 
chasduster said:
u joints will have a shake under accleration.....at any speed not just 3000 and up....so when you unload the drive train by pressing the clutch in the shake is worse?????Like you are coasting right.....try shutting the car off and coast it...see if it shakes then...may have to rebalance tires.....is it in the seat or steering wheel....seat will be rear tires...steering wheel will be front tires....
Click to expand...

can a u joint cause a vibration on right curve or turn only? no vibration on left curve accell?
 
demon seed said:
The very first thing you check is both u-joints. Get underneath the car and grap one yoke with one hand and the other yoke with the other hand and see if there is any looseness between them. Also check that the c clamp nuts that hold the rear u-joint caps into the pinion yoke are tight. Checking the u-joints is not something that you can do by just looking at the drive shaft. A vibration in the seat of your pants, especially one that just started, is 95% of the time u-joints. If this doesn't help get all 4 tires balanced and while the rear tires are off check that the brake drum weights haven't flown off.

Terry
Click to expand...

can a u joint cause a vibration on right curve or turn only? no vibration on left curve accell?
 
SGBARRACUDA said:
Brought back from the dead 6 years and 3 months later! Damn!
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hey! someone reccommended that i read other posts instead of asking questions, so i read a post on the issue that i was looking at, and didnt realize it was old.... very old.... very very old...
 
check your axle end play. With some of the stuff you are finding on this car it might be missing the retainer for the adjuster and have backed off.
 
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