The brief
Mr Ang was referred to us with a disturbing noise coming from the front of his Jetta, and noises like that have a few possible causes that a proper troubleshoot sorts out, a failed driveshaft being one of them. The driveshaft sends power from the gearbox to the front wheel, and it has constant-velocity joints at each end packed with grease and sealed in rubber boots. When a boot splits the grease escapes and dirt gets in, so the joint runs dry and wears, and a worn driveshaft stops doing its job as a dampener and starts making loud friction noises, the tell-tale clunk when you accelerate or shift between drive and reverse, and a vibration on the move. A worn driveshaft doesn't recover, so it gets replaced.
The diagnosis
On the lift the front got a proper troubleshoot, and the worn driveshaft was the noisy culprit, the joint dry and worn, which is the clunking on acceleration and on shifts and the vibration. The other shaft, the gearbox and the rest of the front were sound. That's a driveshaft replacement, rather than chasing a noise that's only going to get worse.
The work
The worn driveshaft was removed and a new genuine VW-spec shaft fitted, the joints and boots fresh and properly greased, every fastener torqued to the manual figures and the hub nut renewed. The other side's boots were checked while it was apart. A road test confirmed no clunking on acceleration or on shifts, smooth drive, and no vibration, all turned around the same day.
The outcome
No clunk on acceleration or between drive and reverse, smooth drive, no vibration, and the Jetta whisper-quiet on the road again, sorted in a day. Mr Ang got the Jetta back quiet and smooth, relieved. A worn driveshaft only gets noisier and less safe, so troubleshooting it properly and replacing it kept a small job small.
