halfshafts

Halfshafts, in automotive terminology, are the drive axle halves that transmit torque from a vehicle’s differential or transaxle to the wheel hub. In front‑wheel drive and many all‑wheel drive setups, each wheel is driven by a halfshaft that carries one or two constant-velocity joints to accommodate steering and suspension movement. In rear-wheel drive and some AWD configurations, halfshafts run from the differential to the wheel hubs or to additional intermediate shafts.

Construction and components: A typical halfshaft is a steel shaft with splined ends that engage the differential or transaxle on one end and the wheel hub on the other. Most front-wheel drive halfshafts include an outer CV joint near the wheel, an inner CV joint toward the transaxle, and protective boots filled with grease to keep dirt out and lubrication in. The joints allow angular motion while transmitting torque, enabling smooth steering, acceleration, and suspension articulation. Materials are chosen for high torsional strength and durability, with heat treatment to resist wear.

Variants and applications: Front-wheel drive vehicles commonly use CV-equipped halfshafts, sometimes called CV axles, with independent inner and outer joints. Rear-wheel drive and some all-wheel drive systems use halfshafts that connect the differential to the wheel hubs, occasionally integrating with other drive components. The exact geometry and joint type vary by design and manufacturer.

Maintenance and failure: The outer and inner CV joints are protected by boots; a torn boot can lead to grease loss and joint wear, resulting in clicking or clunking during turns, vibration, or loss of steering feel. Replacement may involve installing a complete CV axle assembly or replacing individual joints, depending on the vehicle and failure mode. Regular inspection of boots and joints helps prevent sudden drive failure.