noise and vibrations after 4.10 installation
 

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!

Unbolt the driveshaft and rotate it 180°. See if that cures it.

I have 4.10's in my car and I don't have and loud or growling noises at top end....they probably did not use the correct tools to shim the gears and propbably took a guess....

Not Good
 

When I had my gears installed the speed shop was adamant that I take it very easy (keep it under 65 mph) for the first 200 miles to let the gears break in. Since I had about a 100 mile drive home when I picked the car up they told me a should take a break after about 50 miles of highway driving to let things cool down. I pretty much followed their directions and haven't had ANY noises or issues. Anyways, how soon did you go for your little top speed run after they were installed? This speed shop had several examples of bad gear installs, man these things were mangled, some were just twisted all up from incorrect installs and alignments to others which were completed melted down! Anyways good luck with this.