Rumble Under Hard Acceleration (e46 M3)

[danewilson77]

Driveline/tyranny related. Perform fluid swap as a cheap troubleshooting step.



HTC DNA ON TT4 BETA, WILLIAMSBURG, VA

[UdubBadger]

doesn't do much on the trans, ask me how I know.

[UdubBadger]

Ok guys, so i went for a ride in Jim's car and now I am stumped. Any help would be appreciated.

The "sound" is best heard in 1st through 3rd gear between 3k and 4k RPMs. However it is not consistent and can also be heard in other gears but not as loud.

It last for about a second or two, it is a pretty good vibration and a sound that I can not pin point. It doesnt sound like a bushing binding to me or metal. It sounds like it is coming from the center of the car directly behind the front seats.

This is going to sound odd, but it sounds like the sound a Pigeon makes, but louder and slower. That is the only way I can describe it.

Any thoughts?

Remember car is a SMG tranny and the CSB, tranny mounts, and Guibo have all been replaced with no joy in fixing it.

the location would indicate the diff, driveshaft or rear axle. If not those, maybe the wheel bearings?

[M3TA5IN]

the location would indicate the diff, driveshaft or rear axle. If not those, maybe the wheel barrings?

Hm, wheel bearings. Interesting with the sound now that you mention it. However it is coming from a very odd spot but I guess it could be vibrating through the driveline.


Sent from my fancy city machine.

[UdubBadger]

Well the issue with that is you'd likely not hear it through the gears but rather at certain speeds. If it's at certain RPMs it's most likely the drive shaft between the tranny and the diff.

[M3TA5IN]

Well the issue with that is you'd likely not hear it through the gears but rather at certain speeds. If it's at certain RPMs it's most likely the drive shaft between the tranny and the diff.

I keep thinking CV joint, makes sent with the miles if its original, but they have taken the driveshaft off and looked at I don't see how that could be missed.


Sent from my fancy city machine.

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Unless a vibration is being passed back up from somewhere else, it really seems like driveshaft or diff from the location of the noise.

Looking at this driveshaft. At least on that the U-joint will be replaceable in the future.

The shop I took it too for the Guibo and CSB charged me $400 for labor. That seemed a little steep, but I've never done them before. I can't imagine replacing the driveshaft would be any different then swapping the Guibo and CSB (maybe slightly cheaper if the driveshaft comes with the CSB already on it). Does $400 sound high for the job?

[UdubBadger]

Depends on the shops rate, sound like 3-5 billable hours is about right.


- Going HAM mobile

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Anyone have any strong feelings if this type of issue could be caused by diff mounts? I'm not sure when (if ever) the diff mounts were replaced. That would probably be a heck of alot cheaper than getting a whole new driveshaft, but I'm not sure if it could cause a problem like this.

[danewilson77]

I'm at 183k and never changed diff mounts.

Just a data point.

HTC DNA ON TT4 BETA, WILLIAMSBURG, VA