I have a 2000 ss camaro 4l60e trans.. it used to vibrate alittle before at higher speeds. i just had the trans rebuilt and also a new flexplate. it vibrates when im at 70 but not an gets a bit worse when your going faster as well as when you drop the gear an go. its annoying cuz i just rebuilt it, now can it be a possibility that its the driveline? or is it just simply something going on with the trans? please help

 

Is it possible your driveline is out of phase? Not sure if its a two piece line or not.

 

May want to verify that the new flex plate is balanced properly for your engine. The drive shaft should be the one piece type.

 

Its one tube so one piece I take it. And it has a harmonic balancer an its a new flexplate and only one way to put it on. One section of the flexplate has 3 holes that aline with the 3 holes on the back of the engine block. Flexplates for these dont have weights on them.

 

did you by chance switch to a poly trans mount.

 

These types of Vibrations are rarely from the transmission itself. If something is made or installed so badly it can cause a vibration you can feel the trans will not last 100 miles anyway.

First we can start with the terminology. “Shaking” is something out of balance or out of round. A “Shimmy” is vibration that is cause by stress.

With most vibration there is a peak harmonic (where the vibration is the worse) like a tire out of balance that shakes real bad at 60 MPH is feels better at 50 and 70 MPH. They teach you in vibration class (yes it is a class) you can never get rid of a vibration you can only move the Harmonic peak out the normal operating RPM range.

Shaking is regardless of engine load BUT in some cases load can make the vibration more noticeable. One thing I do is find what speed the vibration is worse and slip the car in to neutral. Does it vibration go away 100% or 80% or stay the same?
There is a very limited list of things that can cause a shimmy. The list for what can cause a shake is pretty simple, anything that rotates.

Step one is figuring out if it is a shimmy or a shake. Do you have access to an Iphone or Ipod? A mechanic should have a Reed tachometer which measures vibration. There is a Iphone App that can measure vibration. So if you can get one you can measure Harmonics and amplitude of the vibration if the harmonic stays the same and the amplitude drops when you let of the gas you have a shake if the vibration disappears when you let off the gas you have a shimmy. Next you want to look at the scale of the harmonic and convert that to vibration per minute. Then take the speed you where traveling when you took the harmonic measurement and see what part of the car was turning that fast.

Or you can throw parts at it and hope.