increasingly use them on the tailshaft. CV boots and lubrication A separate flexible cover is usually installed over the CV joint, to protect it from foreign particles and prevent the lubricating grease from leaking out. This cover is usually made of rubber and called a "CV boot" or "CV gaiter". Cracks and splits in the boot will allow contaminants in, which would cause the joint to wear quickly as grease leaks out. The CV joint is usually lubricated by molybdenum disulfide grease. The six spheres are bounded by an anti-fall gate that prevents the spheres from falling when the shaftings are perfectly aligned. See also Hobson's joint Hardy Spicer Universal joint References Rotating shaft couplings Automotive transmission technologies