I just chucked it in there, myself. I know it happens sometimes, but I don't understand how the driveshaft goes out of phase anyway. Even the stockers are balanced as a shaft assembly, not with the specific trans and axle the car gets. Anybody got any idea what does it??
whoa wait a second....an aluminum driveshaft is balanced? i had pretty bad vibration 3k when i would get into after i installed the new motor. I'm running the stock driveshaft again because that made less vibration. there is still vibration at 3k and it clears up by 3500-4k but its better.
The OEM driveline *components* are loosely balanced at the factory. This would be closer to a dynamic balance, which is why marking the DS is important. You can sometimes see yellow reference dots.
An alum DS is statically balanced so it matters not what it's phase is. Prokiller, there were some fairly large weights on my Alum DS to get it to spec (from the factory). Do you have those?
Since it happened AFTER you installed a new engine, I would look to the tranny/engine mounts. If these are worn or mis-aligned, the whole drivetrain would cause a vibration.
whoa wait a second....an aluminum driveshaft is balanced? i had pretty bad vibration 3k when i would get into after i installed the new motor. I'm running the stock driveshaft again because that made less vibration. there is still vibration at 3k and it clears up by 3500-4k but its better.