Gentelmen

A few days ago I was driving to work at about 65 MPH and suddenly a noise sounding like marbles from inside the transmission occured. When slowing down I noticed the noise frequency and amplitude tracked road speed only. There was no observable change in the vehicals performance characteristics. At first the noise pretty much disapeard below 10 MPH. Now I have to get up to about 60 to get is started and it will remain until I reduce speed below 40 MPH.

Of course when I got it home and put is on jacks, it wouldent happen at all. I did notice what appeared to be an out of balance condition from either the wheels or drive shaft when I was running it on the jack stands. Tires are new and recently balanced.

I have a couple of questions

1) Is the transmission governer removable with the tranny in the car and might this be the problem.

2) Is there a way of knowing how much drive shaft imbalance is too much and is there a balance proceedure.

3) Does anyone have any other ideas what of what could be wrong.

John Roncallo