G37 Gearbox Rumble


New member
I have a problem and I hope the collective wisdom can help.
G37 coupe, 6 speed, 107k.

The slave cylinder went out. The shop, with my approval, replaced the dual mass flywheel with a solid one, replaced the clutch cover, disc, T/O bearing, pilot bearing, slave cylinder hose and slave cylinder. (not cheap, but reasonable)

On the way home from the shop there was an added noise when driving. At first I thought it might of been a loose heat shield but the noise wasn't tinny enough. The noise was a low rumble. You couldn't hear it above ~2k rpm, but I think it was getting lost in the other road noise.

After trying different things I found the noise was most noticeable at idle. It sounds very much like a bearing. When you push the clutch in, it goes away. As you let the clutch out it is loudest when the clutch is midway and quiets a little with the clutch fully out.

The shop had put in GL5 fluid and thought that might be it. They changed it back to GL4 with no difference. The tech used a stethoscope and said is was a rotational noise coming from the gearbox. Gears don't rumble but bearings do.

So, that's where I'm at. Any thoughts?




New member
I have the same issue in my 07 G35S with a 6 speed Manual Transmission.
I have taken it to several mechanics and I have not been able to figure out the issue.

The problem started in my car after having the Clutch and CSC replaced.
The transmission was replaced and I still have the same issue!
The noise seems to be louder when it is cold outside; especially under 40 degrees

Let me know if you come with any answers,