I know these kind of problems are generally difficult to diagnose online, but I'm hoping someone with this same problem has found out what it was.

My 240D has a popping noise coming from the rear right whose frequency is related to the speed of the car and it's there only under light throttle and higher weight load, such as when making a left turn or carrying a heavy passenger. I think it's either the RR wheel bearing or axle shaft, but which one? Basically I don't want to replace one of these and then find out it was the other item. Or could it be something else? The car has no vibration and I've done a visual inspection of the undercarriage, including the flex disc.

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2004 VW Jetta TDI (manual)

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