vibration
 

I have a vibration problem somewhere in my driveline. It isn't too bad at idle but continually gets worse at higher RPMs. You start to notice it about 3000RPMs. Last week I just put on a new clutch and resurfaced the flywheel..both of which were torqued to specification. The trans is pratically brand new and I just bought a new aluminum driveshaft. I busted one of the bolts off the rear trans mount so I am thinking that is the problem. I was just wondering if a loose transmission mount would cause a decent vibration. Let me know if you guys have any other suggestion as to what the problem might be. Thanks, Jason.

Where are you feeling this vibration? Be specific.

It feels like it is somewhere between the flywheel and rear end.

Tire out of balance? Something in the rear end?

The rear end is about 2 months old and it wasn't giving me trouble before and the tires are brand new and freshly balanced.

Re: vibration
 

Sounds like that's your problem right there.

Okay, you need to define if the problem is rpm specific, or mph specific. If it's rpm specific, like you said, then it has to be caused by something between your engine and tranny. If it's mph specific, then it's a problem somewhere between your tranny output shaft and your wheels.

Take care,
~Chris

the problem is definately rpm specific. it isn't very bad between idle and 3 rpm's, but gets continually worse after 3 rpm's.

Okay, one last question: Will it happen in neutral, or only when you're driving?

Yes it does the same thing in neutral. I hooked up the new trans mount and the problem is still there. The clutch I bought was knd of cheap, but new. Do you think that maybe it wasn't balanced very well? Or maybe the machine shop did not balance the flywheel after they resurfaced it.

Since it's rpm specific, that eliminates everything after the output shaft on the tranny (driveshaft, rear end, wheels & tires). Since it does it in neutral, then that eliminates the transmission after the input shaft. That leaves the engine, motor mounts, flywheel, and clutch. Check the motor mounts first. Since your engine relies on external balancing, I would suspect either a problem with the harmonic balancer, or the flywheel. Check you timing, and make sure the marks haven't moved. Then rev the engine to the point of vibration, and observe the balancer. If it looks fine, then I'd go after the flywheel.

Take care,
~Chris

I had the flywheel resurfaced, do you think maybe it threw the flywheel out of balance? I figured that it wouldn't change anything as far a balance since they took the same amt off on all sides. I was just curious cause the problem did not happen until I resurfaced it and put it back on.

We've got the same symptoms - except our stang's vibration seems to go away after 3K RPMs. We've changed the harmonic balancer, already replaced the motor mounts last year with Energy Suspension. My son dropped the tranny last night so we can look at the flywheel and clutch pressure plate.

Not an expert by any means - but my understanding with externally balanced engines there's two critical points the harmonic balancer and the flywheel for balancing to eliminate vibration.

I had the exact same problem and it was an out of balance pressure plate - especially if you are using a centerforce pressure plate that has weights on it that swing outward to put more force on the clutch...if a couple of these weights are out of whack then it will cause a vibration...

I replaced the harmonic balancer awhile ago so I know that it definately isn't that. The motor mounts are fine too, so it looks like i'll be pulling the tranny out to check the flywheel and pressure plate. I suppose that is what I get for buying a cheap clutch. Thanks for the help guys, I will be sure to let you know how it goes.

Sorry. :(

Sometimes I wish I could just tell people it was some secret bolt you needed to tighten, but it never is.

Good luck.

Take care,
~Chris

We just pulled our clutch out last night and weights are whacked and the teeth are whacked as well on the pressure plate. We've got a CenterForce Dual Friction clutch. I believe part of our problem was on our end when we put the new clutch in didn't have it adjusted right.