2004 330Ci Strange Noise - no codes

[kchinger]

My dad is in town, his car, leaving in a few days. Noise started on the trip and then got worse on their drive up.

It's worst when accelerating between 15-25 mph. Seems worst in 1st gear and gets progressively quieter and less noticeable, even if you're in 3rd at the same speeds it's much less noticeable. Even hard acceleration at higher speeds doesn't cause it. It's a loud, fast clunking.

Turning doesn't seem to effect it. Seems to come either from the transmission tunnel, driveshaft, differential, rear end, something like that.

Sorta sounds like a miss, but the only code is a pending P0440 that I think is probably unrelated. It also doesn't happen at high speed, low rpm, high loading when a miss should be worst. And doesn't sound like quite the right location although sounds in cars travel all over.

Jacked it up and the CV joints at the rear look fine, no play, no grease leaking.

The driveshaft rubber joints were replaced but not recently and we haven't checked them yet.

It's strong enough that you can feel it in your butt and your hand resting on the console for example.

Any ideas? My dad is a really, really good mechanic and I'm not a terrible one and we're kinda stumped and running out of time.

[sgtfury40]

Csb?

[kchinger]

Seems promising. If we get it up on ramps or jacks is it pretty obvious to check?

[E39 Newbie]

Seems promising. If we get it up on ramps or jacks is it pretty obvious to check?

I'm with CSB, too. But it's a PITA to check because you have to take off the exhaust, and drop the heat shield.

[kchinger]

I'm with CSB, too. But it's a PITA to check because you have to take off the exhaust, and drop the heat shield.

Damn. I was hoping it could be checked without getting all that off. Might as well replace it at that point, lol

[kchinger]

They ended up doing the CSB and went ahead and did the rubber joint at the front of the driveshaft because why not while you've got it apart.

It fixed it. Not sure which it was for sure.

[E39 Newbie]

They ended up doing the CSB and went ahead and did the rubber joint at the front of the driveshaft because why not while you've got it apart.

It fixed it. Not sure which it was for sure.

It was probably the CSB. I had a very worn out GUIBO and they don't make noise, they flex a lot and it feels "funny" when you put the car into gear, if that makes sense.