TOYOTA/LEXUS 4347080018 CV JOINT

The CV JOINT is the outboard constant velocity joint that connects the outer end of the drive shaft to the wheel hub, transmitting engine torque from the shaft to the driven wheel at all steering and suspension angles without introducing rotational speed variation — the constant velocity characteristic that distinguishes this joint from a simple universal joint that would produce cyclic speed fluctuation at any angle. The Rzeppa ball-and-cage design used in virtually all current front-wheel-drive and AWD outer CV joints consists of a hardened steel outer race bolted or pressed into the wheel hub flange, six precision-ground steel balls retained in a steel cage between the outer race and the inner race splined onto the drive shaft stub, and six Gothic-arch ball grooves machined into both races at a geometry that forces the cage and balls to bisect the angle between the shaft and the hub at all operating angles — this bisecting plane geometry is the physical mechanism that eliminates speed variation through the joint. The outer joint must accommodate the full steering lock angle — up to 47–52 degrees on modern platforms with tight turning circles — without binding, noise, or torque interruption; it is sealed by a rubber or thermoplastic CV boot held by two clamps that retains 80–120g of molybdenum disulphide or lithium-complex grease providing lifetime lubrication for the ball and race contact zones.

This unit — TOYOTA/LEXUS 4347080018 — is manufactured to OEM-equivalent specifications: outer race spline count and diameter for hub engagement, hub flange bolt circle and stud thread for wheel attachment, inner race spline for drive shaft engagement, ball diameter and cage pocket geometry, maximum operating angle, boot clamp positions, and grease type and fill quantity are matched to the original part. Supplied as a complete joint assembly with pre-packed grease and boot. Available wholesale from 7.02 USD, MOQ 300 pcs, production lead time 40-50 days.

Outer CV joints fail almost exclusively through boot failure — road grit entering through a torn or cracked boot abrades the ball and race surfaces within a short operating period as the molybdenum grease is contaminated and loses its extreme-pressure properties; the ball raceway surfaces develop pitting and spalling that produces the characteristic clicking noise on tight turns within weeks of boot failure. Unlike the inner joint which can sometimes be cleaned and rebooted when the boot tears early, the outer joint operates at larger angles and higher contact stresses that accelerate contamination-induced wear; a joint that has been running with a torn boot for any significant mileage requires complete replacement. Boot inspection at every service interval is the single most effective preventive measure for outer CV joint longevity.