Noise from the rear: New M3 owner

[f4im3]

Hopefully this is in the right forum

On decel with trans in neutral at any speed under 20 I can hear what sounds like a "card in the spokes", like a gurgling or fluttering. Has anyone come up with a fix for it? Changed the diff fluid with no change in the sound. I also get the noise under very light throttle at any speed, or transition from decel to accel.

I am beginning to suspect the driveshaft/differential. Any ideas?

Thanks

[Erik@EDGE]

Get under there and make sure the heatshield isn't rubbing on the driveshaft or halfshafts.

[f4im3]

Got under the car and I do not see anything rubbing on the driveshaft or halfshafts. I did find both muffler hangers broken so I replaced them. Noise is still there, at least I confirmed that I do need rtab's, completely torn.

[Erik@EDGE]

do you mean RTABS or Rear SHock Mounts? Can't see the RTABs without dropping the carrier. If you have over 50k, its a good idea to do both anyway.

[Erik@EDGE]

are you running stock wheels? Spacers? if so, and if you are running longer bolts for the spacers, that could be the problem. A little too long on the rear will cause the bolt to contact the e-brake parts and make that clicking sound.

[f4im3]

I am running stock wheels/ lugs. I suppose I could remove the lugs and measure them to make sure they are standard size. I removed the driveshaft ot inspect the u joints. They look ok, but I am sending it to a specialist for inspection anyway. I may pull off the rear rotors to see if anything is rubbing. Thanks for the tip. I can just see part of the bushing inside the trailing arm and it looks torn. I put a prybar between the arm and body and the arm moves around the center of the bushing. The rear shock mounts appear to be ok. Anodized blue with rubber inserts. What manufacture are they?

Shane

[monterey]

sounds more like a rotor problem to me..

[GabbyGM3]

I HAD THAT SOUND AND MY SERVICE ADVISOR PUT SOME ADDITIVE THAT LASTS FOR 100,000 MILES THAT MADE THE NOISE GO AWAY. IT'S NOTHING TO REALLY TO WORRY ABOUT THOUGH.

[f4im3]

What kind of additive? and where did he put it?

[Def]

When my RSMs were toast they make a rattling sound. Kinda like hollow plastic on metal tapping really quickly. This was the metal sleeve inside rattling around instead of smoothly controlling the shock's motion.

It seemed to really only happen at lower speed "ripples" in the pavement. Not bumps so much as just high frequency undulations that caused alot of low amplitude shock motion.