See Figures 1 and 2
The CV (Constant Velocity) boots should should be checked for damage each time the oil is changed and any other time the vehicle is raised for service. These boots keep water, grime, dirt and other damaging matter from entering the CV-joints. Any of these could cause early CV-joint failure which can be expensive to repair. Heavy grease thrown around the inside of the rear wheel(s) and on the brakes can be an indication of a torn boot. Thoroughly check the boots for missing clamps and tears. If the boot is damaged, have it replaced immediately.