Drivelines and axles

FWD axles u Drive axles for FWD commonly called half shafts u 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 u Most use a sealed front wheel bearing

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

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

CV service u 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 u Running wheels off of ground can damage joints u Moisture / dirt in joint from ruptured boot is death to the joint

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

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

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