Troubleshooting Guide
| Problem | Possible Cause | Corrective Action |
|---|---|---|
1. Fractured cross or trunnion or bearing cup. | A. Excessive running load. B. Shock load. C. Insufficient joint capacity. D. Excessive running angle. | A & B & C. Replace with higher capacity driveshaft and U-joint. D. Reduce U-joint angle |
2. Early life U-joint failure | A. Inadequate lubrication. B. Seal failure. C. Excessive running angle and excessive speed. D. Excessive running load. | A. Lubricate at minimum recommended intervals with recommended lubricant. B. Replace U-joint. C. Reduce running angle. D. Replace with higher capacity driveshaft and U-joint. |
3. Galling of U-joint trunnionend and bearing cup pad. | A. Excessive running angle and excessive speed. B. End to end fit too tight. C. Inadequate lubrication. | A. Reduce U-joint angle. B. Replace U-joint. If replacement kit is tight, check yoke alignment and lockup size: replace yoke. C. Lubricate at minimum recommended intervals with recommended lubricant. |
4. Brinnelling of bearingsurfaces. | A. Normal fatigue wear. B. Excessive running angle and excessive speed. C. Excessive running load. D. Needle skewing. E. Improper running angle. F. Inadequate lubrication. | A. Replace U-joint. B. Replace U-joint angle. C. Replace with higher capacity driveshaft and U-joint. D. Replace U-joint; check for yoke distortion. E. Maintain minimum recommended running angle (typically 1°). F. Lubricate at minimum recommended intervals with recommended lubricant. |
5. Slip assembly seizes up. | A. Inadequate lubrication. B. Seal failure. | A & B. Replace components. Lubricate at minimum recommended intervals with recommended lubricant. |
6. Slip assembly galling. | A. Seal failure leading to contamination. B. Excessive running load. C. Inadequate driveline design; length of spline engagement too short, normal running condition with spline at pulley extended position. | A. Replace assembly. B. Replace with higher capacity driveshaft and U-joint. C. Increase length of spline engagement with longer splined stub. Review driveshaft length requirements and rebuild with stub spline centered in yoke at normal running condition. |
7. Stub shaft or tubing failure intorsion. | A. Excessive running load. B. Shock load. C. Inadequate driveline design: tube size too small. | A & B & C. Replace with higher capacity driveshaft. |
8. Failure at tube weld. | A. Improper weld. B. Excessive running load. C. Balance weight welded too close to tube weld. | A, C. Replace tube. B. Replace with higher capacity driveshaft. |
9. Yoke ear failure. | A. Ear, contacted yoke ear of other yoke in assembly while running. | A. Reduce running angles; use yoke with higher angle rating. |
10. Yoke hub failure. | A. Excessive running load. B. Excessive secondary couple loads | A. Replace with higher capacity driveshaft. B. Reduce running angles. |
11. Center support bearingfailure. | A. Seal failure. B. Mated with an oversized stub shaft | A, B. Replace with new components. |
12. Center support rubbercushion failure. | A. Misalignment. B. Located too close to heat source. | A. Replace and align. B. Shield from heat or move away from heat source. |
13. Driveline vibration. | A. Improper assembly. B. Excessive or unequal running angles. C. Defective U-joint. D. Driveshaft out of straightness and balance specifications. E. Worn slip assembly components. F. Driveline length exceeds maximum for speed range. | A. Make sure all snap rings or bolts are fully seated or torqued properly. B. Reduce and equalize running angles. C & E. Replace with new components. D. Straighten and balance. F. Redesign using larger diameter tubing or two piece driveline. |
