Transmission Noise

[rking117]

Hey folks, I have had this weird transmission noise for a couple years now. Sometimes in Drive and comfort mode (not with sport button pressed) When the car switches to 4th or 5th gear under light acceleration I hear this low pitched resonance noise which is accompanied by a vibration. When it happens the noise appears and then immediately stops shortly thereafter without any input changes from my foot or increase in speed. It is most noticeable upon resuming light acceleration when I slow down for ongoing traffic and the RPMs drop down to around 1500 when the car in 5th gear (sometimes 4th or even 3rd the trigger seems to be 1500 RPMs even though i have never heard it in 1st 2nd or 6th gears). When it happens it sounds like the transmission is under heavy load for a second to two and switches in and out instantly. so what is am saying is that the sound doesn't build it is like a light switch it is either on or off without an in between. I will try again to record the sound but thus far it has been elusive to a sound recorder. You can feel it in the steering wheel as well as hear it. the resonance sounds like it drops an entire octave. I drew a picture of what it sounds like to me in a line graph, this is my best guess at how to tell you what it sounds like. Before this noise began the vehicle sounded like it followed the blue dotted line not the violent drop in tone.

Does anyone have any idea of what this might be? And if not how can i explain it to my SA for help? My three attempts so far have failed

I suppose it would be helpful to know that i have the 3.0 with steptronic transmission with sport button not DCT.

[nicknaz]

My GUESS is it is a heat shield that is a bit loose and rattling/vibrating

[Lurcher]

better to post over on the M3 board since they have same tranny, & they get a lot more views.

[rking117]

thanks guys will do

[nicknaz]

Originally Posted by Lurcher

better to post over on the M3 board since they have same tranny, & they get a lot more views.

OP has the 30i with the 6spd torque converter transmission. DCT is shared with M3 but the 6spd torque converter transmission is shared (I think) with the E90 330 and 335

[Lurcher]

Originally Posted by nicknaz

OP has the 30i with the 6spd torque converter transmission. DCT is shared with M3 but the 6spd torque converter transmission is shared (I think) with the E90 330 and 335

Ahh missed the details in my rush to post - but same thought process applies :-)

[rking117]

yeah i thought about it and posted over on the 3er board