The pinion is always offset to the right side of the ring gear. Far as I know any rear end has one side shorter than the other unless it's been cut with equal axle lengths. Then you have the situation your dealing with now. Doesn't sound to me like enough angle to worry with, the only other issue that would cause vibration besides having the shaft to straight would be if the shaft yokes were installed out of phase. This will make one shake like a belly dancer! :lol: