Spicer Driveline Installation Service Manual - Manual (Page 8)

5
Installation Techniques
Universal Joint Operating Angles
Every Universal Joint that Operates at an Angle Creates a Vibration
Universal joint operating angles are probably the most common causes of driveline vibration in vehicles that have been reworked,
or in vehicles that have had auxiliary equipment installed.
Universal joint operating angles are a primary source of problems contributing to:
• Vibrations
• Reduced universal joint life
• Problems with other drivetrain components that may include:
- Transmission gear failures
- Synchronizer failures
- Differential problems
- Premature seal failures in axles, transmissions, pumps, or blowers
- Premature failure of gears, seals, and shafts in Power Take-Offs
When you rework a chassis or install a new driveshaft in a vehicle, make sure that you follow the basic rules that apply to universal
joint operating angles:
RULE 1: UNIVERSAL JOINT OPERATING ANGLES AT EACH END OF A DRIVESHAFT SHOULD ALWAYS BE AT LEAST 1 DEGREE.
RULE 2: UNIVERSAL JOINT OPERATING ANGLES ON EACH END OF A DRIVESHAFT SHOULD ALWAYS BE EQUAL WITHIN 1 DE-
GREE OF EACH OTHER (ONE HALF DEGREE FOR MOTOR HOMES AND SHAFTS IN FRONT OF TRANSFER CASE OR AUXILIARY
DEVICE).
RULE 3: FOR VIRTUAL VIBRATION FREE PERFORMANCE, UNIVERSAL JOINT OPERATING ANGLES SHOULD NOT BE LARGER
THAN 3 DEGREES. IF THEY ARE, MAKE SURE THEY DO NOT EXCEED THE MAXIMUM RECOMMENDED ANGLES.
A universal joint operating angle is the angle that occurs at each end of a driveshaft when the output shaft of the transmission and
driveshaft and the input shaft of the axle and driveshaft are not in line. (See Fig 1)
The connecting driveshaft operates with an angle at each universal joint. It is that angle that creates a vibration.
Figure 1
Engine
Trans.
Axle
Driveshaft
Operating Angles