DRIVE SHAFT

Rear-driven cars with front-mounted engines have a drive or propeller shaft running from the transmission to the differential on the rear axle. On modern cars, it is a hollow shaft connected at both ends by a universal joint. Some drive shafts are in two pieces with a third universal joint between them for additional support. Universals are double-hinged joints with two U-shaped yokes fastened at right angles to a cross-shaped member called a cross shaft or spider. The yokes pivot on the arms of the cross and allow power to be carried through two shafts that are at an angle to each other.

There are two types of universal joints used on today's cars. The conventional type, and the constant velocity or CV type. Larger, more expensive cars such as the Buick, Cadillac, and Lincoln are usually equipped with the CV joint. The disadvantage of the conventional universal joint is a slight vibration set up in the drive shaft each time the rear end of the car moves up and down. To eliminate this vibration, the CV joint has two single joints connected by a steel link or yoke, kept in relative position by a special centering ball and socket. This arrangement usually eliminates drive shaft vibrations while going over a bump or road dip.
While you may replace a drive shaft, you should not rebuild a CV joint. Complete replacement of the entire drive shaft unit with a new one is necessary because the CV joint drive shaft requires special balancing.

In this chapter you will learn how to remove a complete drive shaft assembly, replace the conventional-type universal joint, and install a drive shaft. If the universal joints and drive shaft on your car are en-closed in a torque tube, you should take it to a mechanic for any repairs. Special tools and equipment along with specific adjustments are required when servicing or repairing a torque tube assembly.