What did you do for your M3 today?

[EthanolTurbo]

So I got under the car, there’s nothing wrong, nothing loose, tbh I think it’s the new PowerFlex poly front diff mount making a SHIT LOAD more noise in the cabin. It’s gotta be that plus the fact that I removed the sound deadening. I did also do CMP solid subframe mounts, not sure how much a role those are playing.

I knew I was doing some questionable stuff, and yes I did read all the threads I could find. but I didn’t imagine it would increase the NVH THIS MUCH. I suppose I’ll have to just live with it for a while, until I feel like doing a big pain in the ass job to swap that out, but I feel kind of annoyed at myself for going against the sage advice of the e46 elders and proving them right yet again.

FWIW My old mount was also poly but it was way quieter. I still have the same older poly mounts on the rear of the diff cover. I had to replace the front because I ended up having to replace the entire subframe due to uncovering negligent past repairs, and the old mount couldn’t be saved.

Lol this is why poly diff bushings suck. Under certain load and RPM my poly diff bushing makes more noise than my exhaust does. Swapping back to OEM soon.

[Nate047]

Lol this is why poly diff bushings suck. Under certain load and RPM my poly diff bushing makes more noise than my exhaust does. Swapping back to OEM soon.

Yea dude exactly what I’m finding. Having rear interior removed is for sure exaggerating the problem too. And usually track cars have really loud exhaust that kind of masks it.

[beyondm3]

Got back from a little work road trip after fitting up my new 18” 219M wheels and DWS06 tires. 245/40 front and 275/35 rear. The ride is so much better now than with the old 19” stockers on Firestone summer tires.

SMG remains happy for now with the new gear position sensor. Thinking diff clunk might be my next issue to tackle.

Have you checked your rear diff bolts?

[beyondm3]

A nice polish session with griots ceramic all in one.

[nahvkolaj]

Have you checked your rear diff bolts?

Not recently, but those got replaced with new updated bolts when I had the rear subframe out. Torqued to spec, new front mount bushing and new rear cover. It's been the same experience since I got the car.

[karter16]

Not recently, but those got replaced with new updated bolts when I had the rear subframe out. Torqued to spec, new front mount bushing and new rear cover. It's been the same experience since I got the car.

When are you experiencing the diff clunk? Under what conditions do you notice it?

[nahvkolaj]

When are you experiencing the diff clunk? Under what conditions do you notice it?

Shifting mostly. If I work the throttle juuuust right, I can make it pretty smooth. If I put the SMG setting at 5, I usually get a pretty big “bu-bum” type clunk from the rear.

I get a pretty rapid clunk I can hear in the trans tunnel and out back in slow speed 1st and Reverse (in the driveway, some parking lots).

SMG with CSL software and DME parameters

[karter16]

Shifting mostly. If I work the throttle juuuust right, I can make it pretty smooth. If I put the SMG setting at 5, I usually get a pretty big “bu-bum” type clunk from the rear.

I get a pretty rapid clunk I can hear in the trans tunnel and out back in slow speed 1st and Reverse (in the driveway, some parking lots).

SMG with CSL software and DME parameters

Yeah I wondered if that was when. I had exactly the same thing and for the longest time I thought it was my diff itself (I'd replaced everything else). I then did a complete SMG/clutch relearn using INPA and it made for a very significant improvement in symptoms for me. Thought I'd mention that as if you haven't done it recently it might be worth doing first and seeing if it helps.

Edit: just noted your earlier post when you say you replaced GPS, presume you've already done this then when you replaced the GPS...

[nahvkolaj]

Yeah I wondered if that was when. I had exactly the same thing and for the longest time I thought it was my diff itself (I'd replaced everything else). I then did a complete SMG/clutch relearn using INPA and it made for a very significant improvement in symptoms for me. Thought I'd mention that as if you haven't done it recently it might be worth doing first and seeing if it helps.

Edit: just noted your earlier post when you say you replaced GPS, presume you've already done this then when you replaced the GPS...

Yup did the full INPA bleed and adaptation procedure. With the new bushings and bolts, I don't know what else it could be besides internals. Feels like excess gear lash.

[RC Fresh]

Shifting mostly. If I work the throttle juuuust right, I can make it pretty smooth. If I put the SMG setting at 5, I usually get a pretty big “bu-bum” type clunk from the rear.

I get a pretty rapid clunk I can hear in the trans tunnel and out back in slow speed 1st and Reverse (in the driveway, some parking lots).

SMG with CSL software and DME parameters

Sounds like a similar experience to mine. Clunks under load and acceleration. Solid diff mounts and subframe. Ordered OEM diff covers and front bushings. I'll start there.

[Cubieman]

New fog lights and corners.

[SUPREM3///]

Yup did the full INPA bleed and adaptation procedure. With the new bushings and bolts, I don't know what else it could be besides internals. Feels like excess gear lash.

Did you try slave cylinder/PLCD yet? I just went through something similar. It started to SLAM into reverse/1st, even occasionally it'd shut down along with it. I had a voltage issue as well that may have been more responsible but swapped in a slave/PLCD along with new alternator and battery which took care of it.

Additionally, may be a good idea to flush the CHF fluid if you haven't in a while.

[nahvkolaj]

Did you try slave cylinder/PLCD yet? I just went through something similar. It started to SLAM into reverse/1st, even occasionally it'd shut down along with it. I had a voltage issue as well that may have been more responsible but swapped in a slave/PLCD along with new alternator and battery which took care of it.

Additionally, may be a good idea to flush the CHF fluid if you haven't in a while.

I haven't experienced slamming into 1st/R, it's the slow speed slipping to disengaged clutch where I can hear what I can only think is a combination of diff gear lash and worn dual mass flywheel jiggling.

I haven't flushed the system since I got the car, but maybe that's a good idea. I got a lot of bubbles out of the system last time I bled it.

[maupineda]

Your life will have changed for the better. Oil changes are an absolute breeze with this thing!

Well, I was surprised, I am sure I pulled everything out. Maybe 150-200ml left inside?

[maupineda]

I also scored a used diff which will be rebuilt with my 4.1 crown and pinion and the racing diffs diffs kit. Does 350 sound like a good deal?