VW Golf 5 Inner CV Joint
A worn inner CV joint on a Mk5 Golf usually makes itself known as speed-dependent vibration or a thrumming sensation under acceleration, often more noticeable when the suspension is loaded or the wheels are turned. Because the inner joint manages plunge travel and drivetrain loading at the inboard end of the axle shaft, its wear pattern differs from the outer joint. Choosing the correct replacement means checking spline fit, the protective boot condition, and how the unit behaves during joint articulation before installing it.
The direct answer
When a Golf 5 inner CV joint fails, the practical repair is usually to replace the joint and boot as a matched kit, or to install a complete rebuilt axle shaft if the spline fit or retaining clip area shows damage. The inner joint handles the inboard connection and must slide slightly as the suspension moves, so a new joint that cannot plunge smoothly will transmit harsh drivetrain loading back through the transaxle and the chassis.
Before purchasing, confirm which transmission the car has and whether the replacement matches the original axle shaft diameter and spline count. A joint that looks similar can have a different retaining clip groove or bolt circle. Inspect the old protective boot for splits that let grease escape and road grit enter, and check the visible joint housing for pitting or discoloration. If the joint binds during joint articulation in your hand, reject it before it causes another teardown.