Drivelines and axles

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

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

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

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

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

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

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