Need Advice, Suggestions

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johnmucci

moparmucci
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Ok, so I just got my 66 Dart GT back, I had a 360 engine and an 8 3/4 rear end installed. When you drive the car, especially at 20-40 mph, it vibrates like crazy!!.. as you increase speed the vibration decreases but it is still there, not quite as intense. The tires and wheels were just balanced, the driveshaft was cut and balanced, The motor was dyno tuned, I am at a loss. any ideas??? thanks, John
 
Ok, so I just got my 66 Dart GT back, I had a 360 engine and an 8 3/4 rear end installed. When you drive the car, especially at 20-40 mph, it vibrates like crazy!!.. as you increase speed the vibration decreases but it is still there, not quite as intense. The tires and wheels were just balanced, the driveshaft was cut and balanced, The motor was dyno tuned, I am at a loss. any ideas??? thanks, John
vibrates like in the body or in the susenchen?can you feel it in the sterring?in the break pedel?or both?if its both it is out of balance.sterring.could be bushings.pedal could be a combo.need more info
 
It has a complete new PST front suspension kit, ball joints, etc... The guy that built the motor had a custom made torque converter built by Hughes for the 65 904 tranny that is in the car and a new B&M flexplate..
 
It has a complete new PST front suspension kit, ball joints, etc... The guy that built the motor had a custom made torque converter built by Hughes for the 65 904 tranny that is in the car and a new B&M flexplate..
is it in the pedel?or the whole car shakes?
 
It has a complete new PST front suspension kit, ball joints, etc... The guy that built the motor had a custom made torque converter built by Hughes for the 65 904 tranny that is in the car and a new B&M flexplate..


Put the car in park and then give it gas to see if the vibration happens. If it does the it is in the engine/trans. If it don't post the details on what did happen.
 
Put the car in park and then give it gas to see if the vibration happens. If it does the it is in the engine/trans. If it don't post the details on what did happen.


Sorry I missed this post... Ok I just went out in the garage...started the car in park...reved the motor to about 2500 rpm's no vibration out the norm that I can feel..
 
Do this first before the jack stands.

Check the tires for knots and/or slipped belts.

Was the vibration there before the drive train change? When was the front end built and aligned?
 
Do this first before the jack stands.

Check the tires for knots and/or slipped belts.

Was the vibration there before the drive train change? When was the front end built and aligned?


The tires are like new, only have about 500 miles on them.... the vibration was NOT there before the front end was rebuilt or the drivetrain was changed. It's going to the alignment shop on Monday morning..Also this
vibration is really bad, Is it possibe, just asking, that the shop that cut and balanced the driveshaft got it wrong?? this car drove really nice with the 273 in it, now its like riding in a cement trk...
 
The tires are like new, only have about 500 miles on them.... the vibration was NOT there before the front end was rebuilt or the drivetrain was changed. It's going to the alignment shop on Monday morning..Also this
vibration is really bad, Is it possibe, just asking, that the shop that cut and balanced the driveshaft got it wrong?? this car drove really nice with the 273 in it, now its like riding in a cement trk...

Anything is possible. Could be anything from a bad harmonic balancer to a bad tire. I have had parts that were new that were defective. If you can access a set of jack stands you could jack up the rear end and place them under the axle. Block the front tires and test the car on the jack stands by accelerating it in drive just like you are driving it to see if the vibration is there.
 
When they did the driveshaft did they install new u-joints? Just taking a guess you had a size conversion joint and it got replaced with a straight joint that's not centering properly?
 
Anything is possible. Could be anything from a bad harmonic balancer to a bad tire. I have had parts that were new that were defective. If you can access a set of jack stands you could jack up the rear end and place them under the axle. Block the front tires and test the car on the jack stands by accelerating it in drive just like you are driving it to see if the vibration is there.


Ok, will try that tomorrow and post the results... thanks much, John
 
Ok, will try that tomorrow and post the results... thanks much, John

Basically it is the process of elimination. If you have a vibration with the rear end on jack stands and running the car in drive that would take out the PST suspension parts. If the vibration is there have someone look as you are in the car with it in drive. It might be obvious and something easy to see if you are lucky.
 
When they did the driveshaft did they install new u-joints? Just taking a guess you had a size conversion joint and it got replaced with a straight joint that's not centering properly?


I really don't know, all this work was done in Delray Beach, One would presume that they put new u joints in it...cost me $150 for cut and balance..I didn't take the driveshaft to the shop, the engine builder did and he Installed the engine,tranny etc...
 
its a 65 with original transmission tels me it has ball and trunion type driveshaft.....i just went thru this with the waggin...made the dash shake like crazy...changed out the driveshaft and she's smooth as glass now, that the only thing left that could cause this the way you are describing it, hope this is helpful, for a test remove the drive shaft completely and run her thru the gears...shut down the engine in gear because she wont go into park till the engine stops.....
 
I really don't know, all this work was done in Delray Beach, One would presume that they put new u joints in it...cost me $150 for cut and balance..I didn't take the driveshaft to the shop, the engine builder did and he Installed the engine,tranny etc...

Jack stand test would show that up by watching the drive shaft turning.
 
don't presume they redid the ball and trunion part of the driveshaft the kit ain't exactly cheap
I really don't know, all this work was done in Delray Beach, One would presume that they put new u joints in it...cost me $150 for cut and balance..I didn't take the driveshaft to the shop, the engine builder did and he Installed the engine,tranny etc...
 
its a 65 with original transmission tels me it has ball and trunion type driveshaft.....i just went thru this with the waggin...made the dash shake like crazy...changed out the driveshaft and she's smooth as glass now, that the only thing left that could cause this the way you are describing it, hope this is helpful, for a test remove the drive shaft completely and run her thru the gears...shut down the engine in gear because she wont go into park till the engine stops.....

What waggin said.

Also if you have the original transmission in the car the hub is smaller than the end of the 360 crankshaft. There is a bushing that has to be installed unless a special hub was put on the torque convertor.
 
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