When I hit 4k rpm in my car, I get a terrible vibration that seems to be coming out of my transmission. I had the tranny rebuilt about 5 months ago, and just used a crappy autozone clutch and didnt resurface my flywheel. Also, when I take off from a stop at just normal acceleration, I have a weird vibration sound coming from the front of my tranny. I replaced my mount and had new u-joints installed and my driveshaft rebalanced. The car still does it. The pilot bushing wore out in a few weeks, and I always have a sound from there when I have the car in neutral with the clutch out. Does anybody have any ideas what could cause this vibration? I am thinking it may be clutch/flywheel related.