Check whether your ball joints still have their boots or if the boots are cracked and leaking. Chances are all the ball joints need is some new grease if they're not too worn. One of my ball joints had a missing boot and it was creaking. Like Don said you can verify this by pressing down on the car at each corner. So without removing the ball joint I raised the car, cleaned the ball joint with Super Lubricant, let it dry, then put some wheel bearing grease and resealed it with tape. No more creaking.

As far as replacing the ball joints, you need a special tool for that and it's not a simple DIY job. That funky steering is something you should investigate. Get under there or have someone inspect your suspension for loose/damaged components. You might also want to do wheel alignment.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL