[Yan88gt]

I've just put a new 3.55 gear in my car. When i go at 85 mph i feel a little vibration and i push the clutch or put the car in neutral ,it vibrate very bad. I've check the u joint, wheel bearing, the mark on my driveshaft ,everything is O.k. My wheels are balanced. The car was running great 2 days ago with my old gear.