[E90TL]

Hi all,

I've recently picked up a 2007 E91 320i with 102k miles on the clock. It's had the valve stem seals and timing chain/guides replaced, so I am hopeful it will last for a good few more miles.

I bought the car with a known issue of whining from driveline. The noise is there from about 5mph and remains at all speeds. To me it sounds like gear whine. The noise remains with the clutch engaged and disengaged, and in any gear. The noise changes pitch based on load (on/off throttle), and is linked to wheel speed, not engine speed. Based on other forum posts, I had determined it was the differential, however now I am second guessing myself, and would like some additional input.

The noise is coming from the middle of the car but it's hard to pinpoint. Depending on how I turn my head it sounds like it could be coming anywhere from the gear box to the diff. My question is if it is the diff, would the sound appear as if it's coming from around the shifter? Does the sound of a bad diff travel through the prop shaft and cause the noise to be amplified through the cabin?

I'm aware this could also be an issue with the prop shaft or gearbox so any suggestions are appreciated. Is there any way (without removing the diff), that I can identify what the issue is?

Thanks.