CV Joint

📖 YOUCANIC Automotive Glossary

A CV (Constant Velocity) joint transmits engine power through the drive axle at a constant rotational speed regardless of the operating angle — essential because the axle must accommodate both suspension travel (vertical movement) and steering input (on front axles). Each FWD axle has an inner joint (typically a tripod type allowing plunge/length change) and an outer joint (Rzeppa type allowing high steering angles up to 45+ degrees). Each joint is packed with special CV grease and sealed by a rubber or thermoplastic boot.

CV joint failure is one of the most common FWD repairs. The outer joint produces a clicking or popping noise during turns (the signature symptom). The inner joint produces a clunk or vibration during acceleration. Most failures begin with a torn boot allowing grease loss and water/dirt contamination. Regular inspection of CV boots during oil changes catches tears early — replacing a boot is far cheaper than replacing the entire axle shaft assembly after joint damage occurs.