Drive Shaft

     The term driveline generally refers to the parts that transfer power from a vehicle'stransmission to its drive wheels. Front-engine, rear-wheel-drive vehicles have a drivelinethat contains a drive shaft. The drive shaft is a long shaft that transfers power from thetransmission back to the rear axle assembly. The drive shaft has universal joints at itsends.

    Front-wheel-drive and rear-engine or mid-engine vehicle do not use a transmission anda drive shaft. Instead，they use a transaxle and two drive axle assemblies. The short axleassemblies extend directly out of the transaxle to power the drive wheels.

    A drive shaft assembly is illustrated in Fig. 9.9. It typically consists of the followingparts：

    Slip yoke - connects transmission output shaft to front universal joint

    Front universal joint - swivel connection that fastens slip yoke to drive shaft

    Drive shaft - Hollow metal tube that transfers turning power from the frontuniversal joint to the rear universal joint

    Rear universal joint - another flex joint connecting the drive shaft to rear yoke

    Rear yoke - holds rear universal joint and transfers torque to gears in the rear axleassembly.

    The drive shaft assembly has several important functions：

    ·Sends turning power from the transmission to the rear axle assembly

    ·Flexes and allows vertical (up and down) movement of the rear axle assembly

    ·Provides a sliding action to adjust for changes in driveline length

    ·Provides smooth power transfer

    When the vehicle is moving，the transmission output shaft turns the slip yoke. Theslip yoke then turns the front universal joint，drive shaft, rear universal joint，and rearyoke on the differential. The differential contains gears that transfer power to the reardrive axles. The axles rotate the wheels.