A slip joint at one end of the propeller shaft allows the propeller shaft to lengthen or
shorten when the position of the axle changes. A typical slip Joint has a male and female
spline. It usually contains a lubrication fitting and an oil seal. The male spline is a part
of the propeller shaft, and the female spline is fixed to a universal joint. The slip joint is
located at the power input end of a propeller shaft (the end nearest the transmission). It
allows lengthwise freedom of movement of the propeller shaft and still transmits rotary
Construction and Operation
A universal joint is a flexible coupling between two shafts that permits one shaft to drive
another at an angle. It will transmit power while the angle between the shafts is
FIGURE 3. UNIVERSAL-JOINT.
A simple universal joint consists of three basic parts: a journal and two yokes. The two
yokes are set crosswise (at right angles) to each other, and their open ends are joined by
the journal. This construction permits each yoke to turn (pivot) on the journal while
transmitting rotary motion from one yoke to the other.