(N55 6MT) Rattle from transmission I can feel in the shifter

[NickD]

I have a '12 6MT 135i with 107k miles. When I have the music off I can just barely hear what sounds like a rattling, rumbling like sound. I've determined it's coming from the transmission as I can feel the shifter vibrate in sync with the sound while in neutral. I can hear the sound when in gear as well but not feel it through the shifter as distinctly. It kind of has the sound/feel of a worn bearing. I'm not terribly familiar with this transmission, in fact, I've only owned the car for 3 months now.

If it is a bearing, how hard is it to replace? I'm assuming it's a transmission out endeavor and I should also consider doing the clutch at the same time. Is there anything else it could be?

[tracer bullet]

Any chance it's a transmission mount and nothing inside the transmission itself?

[NickD]

I haven't considered transmission mounts. I have an old Miata that started sounding like this, though much worse and it was the the output shaft bearing. So I'm paranoid now. I'll have to get under the car at some point and inspect the mounts I guess.

[NickD]

So after some more driving it's only happening when the car is in motion and follows the speed of the car, not the RPM of the engine. So I'm fairly convinced it's the output shaft bearing. I haven't had a chance to get under the car and I likely won't soon. I don't think it's that bad yet, so I'll hold off for now on doing anything until the weather is more favorable.

[cerealwars]

Just being hopeful, but check your driveshaft carrier bearing and guibo?

[tracer bullet]

Originally Posted by cerealwars

Just being hopeful, but check your driveshaft carrier bearing and guibo?

Agreed, was thinking the same thing. Can't say from experience that's what it is or anything, but it definitely seems to be worth checking on.

[NickD]

Thanks, I absolutely will. I've been looking more into this as well and thinking that is also a likely possibility.