[m4rked1]

So I am typically pretty good at googling car issues and coming up with an answer, but this one has left me scratching my head. Let me start by describing the noise: it is a moderately loud growling / rumbling that seems to come from the front passenger area of the car.

The car: 2007 e92 328xi N51 MT

When I hear it: it is most noticeable at highway speeds but ONLY when accelerating or engine braking, if I keep throttle neutral the sound goes away.

Weirdly the pitch seems more in sync with engine RPM than road speed, but that could be my imagination.

Turning the wheel does not seem to change the noise at all (not a wheel bearing).

I am worried it may be a bad bearing on the input shaft of the transmission, anybody heard of this on one of these cars?

[nsjames]

I doubt it's an input shaft bearing. I've never heard of a 6l series trans having input shaft issues, save for breaking them in the 6l80s, but that's behind massively tuned motors. Do you get the noise in nuetral? if not, it's not input side of the trans.

it's an XI, so I'd suspect front driveshaft, or front half shafts.

[m4rked1]

Nsjames, I do not hear the noise at all in neutral.

Another strange thing is that some days, I struggle to hear it at all, others it’s almost loud.

I would love for it to be half shafts or driveshaft, that is so much more manageable. Anything I can do to narrow it down? Or do I just need to get it in the air and start poking around?

[rjahl]

Originally Posted by m4rked1

Nsjames, I do not hear the noise at all in neutral.

Another strange thing is that some days, I struggle to hear it at all, others it’s almost loud.

I would love for it to be half shafts or driveshaft, that is so much more manageable. Anything I can do to narrow it down? Or do I just need to get it in the air and start poking around?

Giebo would be my first guess

[m4rked1]

It was the front driveshaft. The ujoint on the transfer case side was completely destroyed

[nsjames]

well at least the problem was obvious.

did you replace the joint or the entire shaft?

[m4rked1]

Originally Posted by nsjames

well at least the problem was obvious.

did you replace the joint or the entire shaft?

The factory u-joint is not serviceable, so I had to get the whole driveshaft. Although, I probably would have had to replace it all anyways due to the damage to the shaft. Anyways, $600 later I am good to go.

[nsjames]

I'm a bit more redneck than most BMW owners.

die grind out those stakes, replace joint, drop tack welds on the trunnion caps.

good as new.
tack welding the caps is a 4 wheelers trick to keep from spitting u joint caps not cut for a full circlip. pretty much every dana 30/44 shaft I've ever touched got tacked caps.