E46 rumbling noise

[Warming]

Not directly related but interested to get your feedback, if you've ever had a constant rumbling noise on your BMW before,

Went to look at an E46 auto today, engine sounded fine and autobox was smooth, here was a mild hiss / turbine-like noise pulling away but no nasty clunks, however I could detect a constant rumbling noise.

I popped the autbox into neutral going down a hill and there was no change coasting along.

From the driver's seat I couldn't feel vibration around the transmission tunnel, so am guessing it could be the diff? The seller mentioned something about diff bearings might need replacing. Any ideas on what it could be and the cost to fix?



Cheers


P.S. I drove there and back in another E46 auto (my 2002) and driving this car I can feel a vibrating prop through the trans tunnel, but unlike the car I viewed there is a distinct lack of rumbling which is why it agrees with the seller's impression than it was the diff.

 

[t-tony]

Much more likely to be a rear wheel bearing than the Diff.

Tony.

 

[Warming]

Thanks, I did wonder if it was wheel bearing. I couldn't detect any clunking from the diff on stabbing the accelerator on and off. The car also had winter tyres fitted!

 

[the Nefyn cat]

In that case I'd try swapping the winter tyres first, they can be somewhat noisier than normal ones. And then I'd suspect a wheel-bearing. If you look on youtube there seems to be quite a few videos about changing bearings, I did have a horrible rumbling from mine but it disappeared when I had a new set of tyres fitted after I repainted the wheels. Must have been a dodgy tyre.

 

[Warming]

Many thanks chaps, tyres are relatively simple to swap, will try that first.