Vibration

[Paul F]

can anyone help me with a vibration in my 74 c3 350 Muncie 4 speed, at 3500 RPMs in each gear it vibrates badly through the transmission and through the car. I’ve had some people say it could be the half shaft joints, but I think that would increase with speed and continuously get worse the faster you go. My vibration is only around 3500 and up and in all 4 gears each . When I am sitting still and the car is in neutral and I raise the rpm slowly all the way up to 5500 rpm I have no vibration, any help would be great

 

[Rruuff Day]

can anyone help me with a vibration in my 74 c3 350 Muncie 4 speed, at 3500 RPMs in each gear it vibrates badly through the transmission and through the car. I’ve had some people say it could be the half shaft joints, but I think that would increase with speed and continuously get worse the faster you go. My vibration is only around 3500 and up and in all 4 gears each . When I am sitting still and the car is in neutral and I raise the rpm slowly all the way up to 5500 rpm I have no vibration, any help would be great

Hello Paul. Welcome to the forum. Sorry. I can't help you with the C3 but would suggest posting in this section as well that may get more audience.

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[Murray20c8]

Does the vibration change in speed and pitch the faster the engine RPM?
It's obviously not speed related so it can't be after the tranny.
I wonder if one of the weights hasn't fallen off the flywheel.

 

[Rruuff Day]

Does the vibration change in speed and pitch the faster the engine RPM?
It's obviously not speed related so it can't be after the tranny.
I wonder if one of the weights hasn't fallen off the flywheel.

He does say only at 3500 rpm. I thought flywheel as well except he says in neutral he doesn't get the vibration at all. I would wonder if @Paul F has any other weirdisms or noises or vibrations when he depresses the clutch to shift... maybe a clutch/clutch fork/throw out bearing/slave cylinder problem...then again, what do I know... lol..

 

[Roughrider]

I have no experience with the c3 model but I'm thinking along the lines of the U Joints as well. Can you get the shafts off to see if they are seizing?

 

[Murray20c8]

I have no experience with the c3 model but I'm thinking along the lines of the U Joints as well. Can you get the shafts off to see if they are seizing?

If it had anything to do after the tranny it wouldn't be at 3500 rpm in all gears.

 

[Dave91TM]

I had an old mustang once , bad U joints, was ok in town , shook like hell at highway speeds.