Spicer Drive Axles Failure Analysis Service Manual - Manual (Page 22)

Ring Gear and Pinion
21
Fatigue Failure
Ring Gear - Catastrophic Fatigue Failure Ring Gear - Start of a Fatigue Failure
Drive Pinion - Torsional Fatigue Failure Drive Pinion - Tooth Fatigue Failure
General Description: Progressive destruction of a shaft or gear teeth. Extremely high rotating and bending forces produce
the initial crack. The crack progresses to the center of the core resulting in complete failure.
Usual Causes: • Overloading the vehicle beyond rated capacity
• Abusive operation over rough terrain
Failure Prevention: • Correct Specifications - see Failure Prevention Section
• Torque is Important - see Failure Prevention Section
• Vehicle Load Ratings - see Failure Prevention Section
• Drive Practices and Vehicle Operation - see Failure Prevention Section
Beach
Marks
Fatigue crack
Star or spiral
fracture
Beach
marks