"Chattering" sounds from tranny, whats causing it???

[GoldenOne]

While hunting for a parking in the garage tonight I noticed a kind of chattering sound I think is from the tranny. It seems to only happens when I take off slowly(both forward and reverse), maybe the clutch??? Help!

[genphreak]

While hunting for a parking in the garage tonight I noticed a kind of chattering sound I think is from the tranny. It seems to only happens when I take off slowly(both forward and reverse), maybe the clutch??? Help! 1. Check the fluid level in the tranny by the exact procedure in the manual.
2. If not that, suspect your guibo (if it has one) or the centre bearing (in the middle of the drive shaft). Noise comes from the area just behind the front seats (but under the car). :) Nick
* beware- perhaps it is just the heat shield loose on the cat or between the exhaust and the drive-shaft, or the drive shaft tunnel and the body (tho these are usually a very tinny rattle).
3. Make sure you change your tranny oil and filter regularly, if you don't it will die, don't risk it so always assume any Previous Owners did not. It is perhaps a good idea to do diff and brake fluid at the same time if at all unsure. :) nick

[Bill R.]

its the normal rattling noises of the dual mass flywheel and the transmission. This noise is considered normal for it. When the engine slows down past a certain point such as when you shut it off you hit a certain rpm where the dual mass rattle happens briefly. When you let the clutch out such as a low speed driving in a parking garage the engine rpm can also drop to that point at which you'll hear the rattle. Other possible causes are broken transmission mounts, guibo or differential mounts and even rear subframe bushings. Try opening the door or rolling the windows down and shutting the car off in neutral and see if you briefly hear the same sound as the engine is coasting to a stop.http://www.bimmernut.com/%7Ebillr/images/dualmass-1.jpg








While hunting for a parking in the garage tonight I noticed a kind of chattering sound I think is from the tranny. It seems to only happens when I take off slowly(both forward and reverse), maybe the clutch??? Help!

[GoldenOne]

thanks guys, ill try and test it again hopefully tonight...lets hope its that normal sound and nothings broken!

Also, whats a guibo??? sounds like a foreign gelatin treat ;)

[GoldenOne]

well after work tonight I had the whole bottom half of the parking garage to myself so needless to say I circled around at slow speeds trying to diagnose this thing. Turns out that it only happens when im below 1000RPM (approx 700-900) in both forward and reverse but no "chattering" noise when I shut off the car. I hope I can conclude that this is the dual mass flywheel making the noise.

BUT I did notice that when I shut off the car, I heard a noise coming from what I think is the dash/front area of the car (most likely A/C?). To me, it sounded like a little electrical actuator turning to a point, then clicks, and repeats a couple times...amazing what I can hear with music off and a completely silent(almost scary) parking garage...

[genphreak]

BUT I did notice that when I shut off the car, I heard a noise coming from what I think is the dash/front area of the car (most likely A/C?). To me, it sounded like a little electrical actuator turning to a point, then clicks, and repeats a couple times...amazing what I can hear with music off and a completely silent(almost scary) parking garage...Amazing what some troubleshooting can do... btw sorry (and thanks Bill) - I didn't notice you were running a manual so you can forget that stuff I said about the fluid... but form what you describe it sure sounds like the twin plate shimmies that make most people swap to a single plate setup- but that's more with e32/34 M30 cars- 525/530540s might well be a different story- Any comment Bill?

Noises shutting down in the dash/firewall are usually just dash stepper motors that run the cabin ventilation flaps. If not that, it was probably the windscreen wiper pressure device or perhaps the ebox fan, they both live uip there in the firewall area under the windscreen. Mine go off at weird times... Good luck... :) nick