Drivelines and axles

1. Drivelines and axles

2. FWD axles • Drive axles for FWD commonly called half shafts • Half shafts allow wheels to turn and have suspension movements • Half shafts consist of inner CV joint, axle shaft and outer CV joint • Most half shafts are unequal length causing torque steer • Most use a sealed front wheel bearing

3. Constant velocity joints • CV joints deliver uniform torque through wide range of angles • Inner joints must be plunge type • Outer joints usually have wide range of angles and do not plunge (Rzeppa) • Joints must operate in a sealed and clean environment

4. CV boots • Boots must seal joint and grease • Common failure point on outer joint • Axle and joints must be removed to replace boot and grease • Only solid boots should be used • May need special tools for clamps

5. CV service • Normally a failed joint will cause noise • Clicking joint on turns is usually outer CV • Vibration during accel/decel and /or clunk usually inner CV • Running wheels off of ground can damage joints • Moisture / dirt in joint from ruptured boot is death to the joint

6. RWD drive shafts • Drive shaft connects transmission to rear axle • May be called propeller shaft • May be one piece or two piece if needed due to angles • Will have at least two u-joints • Will have critical balance weights

7. U-joints • Similar to CV joints in purpose but not as flexible • U-joint angles must be similar to cancel each other • U-joints must be phased to eliminate vibration • Front yoke of driveline must be able to plunge in and out on transmission output shaft

8. U-joint service • Can be retained in yoke by outside or inside snap rings • Can be retained by injected plastic • Defective u-joints will normally cause vibrations • Worn joint may cause clunk on accel • Most joints are permanently lubed • Some replacement joints have lube fitting