Drive Shaft Phasing | Driveshaft U Joint Phase, Yoke Alignment

Phasing is the correct alignment between yokes at each end of the shaft. If the yokes are not in phase, speed fluctuations will not be cancelled out. These fluctuations cause vibration, which may damage components on the engine and the Jet pump.
On most applications the yokes are commonly in phase when the yoke ears are parallel to each other. Sections of the shaft assembly have line-up arrows to assist in phasing.