DIFFERENTIAL MAINTENANCE
Cars with rear-wheel drive or all-wheel drive and 4 × 4s have differentials as part
of the drivetrain system. The only maintenance required for the differentials is to
check the fluid level every oil change. The technician should check the gear
lubricant for proper level, color, and consistency. Low lubricant level indicates a
leak, a milky color indicates moisture in the lubricant, and the presence of metal
indicates mechanical wear. Check your owner’s manual for the recommended
fluid change intervals for your particular vehicle.