Setting Pinion Angle Correctly
Don't know how to set your pinion angle? Read on!Note the angle of the U-joint (shown in red). The angle constantly changes as the U-joint rotates, causing the driveshaft to speed up and slow down as it rotates.This represents a standard driveshaft setup that is done correctly. Note how the angle of the pinion is parallel with the angle of the transfer case output. Pinion and transfer case output angles are shown in orange. The drive shaft angle is exaggerated in these drawings.Another way that a standard drive shaft could be set up correctly. This is a situation that is typically encountered when the transfer case is lowered. Note how the pinion angle has been raised to be parallel with the transfer case output shaft.This is a standard drive shaft setup that is going to cause vibrations. Notice how the pinion angle is very different from the transfer case output shaft angle.Here is a CV type setup that is done correctly. The pinion should be 2 degrees below being pointed straight into the drive shaft.Here's an improperly setup CV system. The pinion should be pointed into the driveshaft rather than parallel with the transfer case output on this type of setup.
Pinion angle is one of the more important measurements on a lifted vehicle. The wrong angle can lead to vibration and premature failure of U-joints, drive shafts, pinion bearings and even transfer case output bearings.
Types of drive shafts
There are two common types of drive shafts used in 4wd vehicles, standard with one U-joint at each end and CV drive shafts. CV stands for Constant Velocity. CV drive shafts are so named because they have a constant velocity joint at one end, the other end has a single U-joint.
There are two types of constant velocity joints, the double cardan and the caged ball type. The double cardan type is the CV joint with the two U-joints at one end that is so popular with 4 wheelers. The caged ball type is similar to a CV joint in a front wheel drive car or a Birfield from a Samuri or Toyota front axle. The caged ball type CV joint is notoriously weak and is it fortunate that these drive shafts can be found in only a few four wheel vehicles including some Bronco II's and a few early XJ Cherokees. Most who find caged ball type CV drive shafts on their vehicles quickly upgrade to a standard double cardan type CV drive shaft.