GMC 88967027 Companion Flange

Power is transmitted from the front differential/axle to the front wheels through a pair of axle shafts equipped with sliding constant velocity (CV) joints capable of both angular and axial motion. The inner ends of the axle shafts are bolted to an axleshaft connected to the differential side gears, while the outer ends have a stub shaft that is splined to the front hub and bearing assembly and locked in place with a large nut. The outer ends of the axle shafts are equipped with ball-and-cage type CV joints capable of angular but not axial movement. It is important to inspect the boots periodically for damage and leaking lubricant, as torn CV joint boots must be replaced immediately to prevent damage to the joints. If a boot is damaged, the CV joint can be disassembled and cleaned, but if any parts are damaged, the entire axle shaft assembly must be replaced as a unit. Symptoms of worn or damaged CV joints include lubricant leaks, clicking noise in turns, clunk when accelerating after coasting, and vibration at highway speeds. To check for wear in the CV joints and axle shafts, grasp each axle and rotate it in both directions while holding the CV joint housings, feeling for play indicating worn splines or sloppy CV joints. It is also important to check the axle shafts for cracks, dents, and distortion.