Rattling from under car

[justinde]

Hey,
my e36 m3 is making a very annoying rattle/whirring noise. the noise is most apparent between 3500 and 2500 rpm as rpm drops. it happens in and out of gear. i can also slightly hear it over the engine noise on acceleration within a wider rpm range. noise sounds like it is coming from the passenger side of the car almost directly below the passenger seat or trans tunnel area. ive listened to the noise from under the car but cant tell exactly where its coming from, either the manual trans or the exhaust. i dont see any heat shield hitting the exhaust and the rattle has been consistently happening ever since i got the car about a year ago. im hoping its not the transmission itself. i have a video to show exactly what it sounds like. it is clearly audible. PLEASE HELP ITS SO ANNOYING

https://www.youtube.com/watch?v=nAUA...ature=youtu.be

[LockDots]

Interesting, but I doubt it's the transmission if it's making that sound in neutral because the transmission is essentially detached from the engine. Exhaust leaks are usually fairly apparent over the rpm range.

[marvinstockman]

Check for loose cat converter heat shield. A couple of large metal hose clamps strung together usually quiets the racket.

[TostitoBandito]

Check the thin metal heat shielding that sits between the exhaust and drive shaft in the tunnel and make sure it's not bouncing around and hitting things.

[scooper]

flex disc

[justinde]

The flex disc cant make noise if its not spinning

- - - Updated - - -

Got under the car again and the noise DEFINITELY sounds like its coming from the transmission. Anybody know of any rebuild videos or diagrams of s5d 320z transmission?

- - - Updated - - -

Also the transmission is never disconnected from the engine unless the clutch is pressed in. So the shafts are still spinning inside it even though there are no gears engaged.

[LockDots]

Correct, that's why I said essentially. I guess I should have been more clear.

Sent from my SAMSUNG-SM-G920A using Tapatalk

[justinde]

No biggy. But now that i think of it, it still makes the noise when the clutch is pressed. So i guess it cant be the transmisson. My ears must just be getting fooled by the noise reverberating off other parts. Maybe my cat is broken on the inside....

[fasteddie313]

Hear the rattling noise right at like 33 seconds when the engine shuts off..
My 95 makes that noise too and I figured it was something to do with the dual mass flywheel or something and it was common, not something to go tearing the trans out to mess with..

Thoughts?

OP maybe you can find a way to peek into your bellhousing to see if their is any foreign contams in there, evidence of anything rubbing anything..
IDK about the s50/52 bellhousing in specific but know of stories bout small sockets getting dropped into bellhousing access ports and whatnot..

[justinde]

Thats not the noise im talking about. That noise is just the clutch assembly and flywheel slowing down as the engine slows down and stops. The rattling im talking about happens when the rpms drop immediately after i let off throttle. I think if there were sockets and stuff in there it would be making a lot more noise.

[OFFtheWallM3]

Did you ever find out what was causing the issue? What you described is happening with my 1998 M3 Coupe currently, it’s driving me nuts.