noise and vibrations after 4.10 installation

[hmarv347]

Ok, here's whats going on. I wanted to see what may have happened to my top end after 4.10's were installed. It was a deserted part of the highway so i punched it. When I hit about 90 - 100 I started hearing a growl and a vibration from the car. the faster I went the louder it got, it was unbearable at 110. I returned back to the speedshop who installed the gears and they told me there was nothing wrong with the gears after they test drove the car. They didn't feel or hear anything and said the slight noise they do hear was from the transmission. They also said it was because everything was moving much faster than before. This does not sound right at all. I've had my car up to 140 before in fourth with the stock 3.27's and never heard a sound. It was always smooth as silk. This time I was in fifth and could not stand the sound level or the vibration.

Is this normal or what could actually be wrong? As it is now, just driving with traffic and needing to pass someone will be horrific to the ears. This is not making me a happy camper with the gear swap so far.

Help Please!