When the slopes are in the same direction on two connected components, subtract the smaller number from the larger to find the U-joint operating angle. When the slopes are in the opposite direction on two connected components, add the measurements to find the U-joint operating angle. Now compare the U-joint operating angles on your drawing to the rules for ideal operating angles mentioned above. The recommended method for correcting severe U-joint operating angles depends on the vehicle suspension or driveline design. On vehicles with leaf springs suspension, thin wedges called axle shims can be installed under the leaf springs of single axle vehicles to tilt the axle and correct U-joint operating angles.
Wedges are available in a range of sizes to change pinion angles.
On vehicles with tandem axles, the torque rods can be shimmed. Torque rod shims rotate the axle pinion to change the U-joint operating angle. A longer or shorter torque rod may be available from the manufacture if shimming is not practical. Some torque rods are adjustable. Always take the time to call the vehicle manufacturer if there are unusual U-joint operating angle problems or consult a Six States Driveline Specialist .