[Ramos]

Quick update, they’re offering to replace the diff and cover 85% of the cost under good will, I’m taking the offer even though I feel the issue clearly started when the was under warranty over a year ago.

Sterling BMW have been class act all the way.

[MisterG]

Originally Posted by Ramos

Quick update, they’re offering to replace the diff and cover 85% of the cost under good will, I’m taking the offer even though I feel the issue clearly started when the was under warranty over a year ago.

Sterling BMW have been class act all the way.

Have you had the diff replaced? - did it resolve the issue?

[aidanmurphy]

I will update my experience.

I took the car in to BMW for this exact noise (clunk when turning at low speed, coming back onto throttle from almost standstill)

It was determined to be my motor mounts, the drivers side had completely collapsed allowing excess movement.

I replaced them and installed some powerflex street inserts. The clunk has either been completely removed or I have not heard it yet, and the drivetrain feels more responsive than it ever did on the stock mounts.

[smeal4128]

'25 m340xdrive here - anytime I come to a stop I get a slight clunk that sounds like it's coming from the rear axle on the passenger side. It's not the auto brake hold as I'm not completely stopped yet, but could it be something with the diff?

[aidanmurphy]

Originally Posted by smeal4128

'25 m340xdrive here - anytime I come to a stop I get a slight clunk that sounds like it's coming from the rear axle on the passenger side. It's not the auto brake hold as I'm not completely stopped yet, but could it be something with the diff?

Highly unlikely. Most likely a bushing

[AM340iMiami]

I have a 2020 and just had to replace a rear diff bushing because it was cracked. Might want to check that out.

[smeal4128]

Originally Posted by aidanmurphy

Highly unlikely. Most likely a bushing

ok thanks - you think even on a brand new car?

[aidanmurphy]

Originally Posted by smeal4128

ok thanks - you think even on a brand new car?

You'd be surprised what BMW considers "wear items"

Take it into the dealer, it should be under warranty still and just have them inspect it. Sometimes ball joints or bushings just don't hold up out of the factory as they should

If the sound is only happening when you come to a stop, it is almost certainly not your diff so don't worry there

[Ramos]

Originally Posted by MisterG

Have you had the diff replaced? - did it resolve the issue?

Yes diff has been replaced, it was on back order and they kept the car for over a month. Issue has been resolved, for those who are still saying it’s not a diff issue. Yes if it.

I also replaced the fluid after 500 miles and it had a lot of metal shavings.

This has been a hard fought battle with BMW but replacing the diff is the only solution. I would highly recommend sterling BMW if you live in so cal as they are now familiar with this issue and will do the right thing.

[Ramos]

Originally Posted by aidanmurphy

You'd be surprised what BMW considers "wear items"

Take it into the dealer, it should be under warranty still and just have them inspect it. Sometimes ball joints or bushings just don't hold up out of the factory as they should

If the sound is only happening when you come to a stop, it is almost certainly not your diff so don't worry there

Have you even read the thread??
Yes it is the diff, and the thump we are describing doesn’t happen when stopped, it happened when the diff is cold and you almost come to a stop but not quite, then accelerate with the wheel turned. My diff replacement finally solved the issue.

[Ramos]

Originally Posted by smeal4128

'25 m340xdrive here - anytime I come to a stop I get a slight clunk that sounds like it's coming from the rear axle on the passenger side. It's not the auto brake hold as I'm not completely stopped yet, but could it be something with the diff?

Yes, read the thread.

[Ramos]

Originally Posted by aidanmurphy

I will update my experience.

I took the car in to BMW for this exact noise (clunk when turning at low speed, coming back onto throttle from almost standstill)

It was determined to be my motor mounts, the drivers side had completely collapsed allowing excess movement.

I replaced them and installed some powerflex street inserts. The clunk has either been completely removed or I have not heard it yet, and the drivetrain feels more responsive than it ever did on the stock mounts.

Dude, what the heck would motor mounts have to do with a clunking sound from the rear axle ?? Seriously stop giving people bad information. This is a faulty diff issue and BMW knows about it, but they will fight tooth and nail before approving a diff replacement.

[aidanmurphy]

Originally Posted by Ramos

Dude, what the heck would motor mounts have to do with a clunking sound from the rear axle ?? Seriously stop giving people bad information. This is a faulty diff issue and BMW knows about it, but they will fight tooth and nail before approving a diff replacement.

The motor mounts are a key point of security for the drivetrain, having collapsed motor mounts will allow extra play and for slack in the driveline to "catch up" causing a clunking noise. This could indeed be felt from underneath the car and could seem like it is coming from the diff area.

I am simply stating that I had the clunk when accelerating with the wheel turned and after changing the motor mounts, I no longer have it. I had also replaced my diff fluid at 50k and had absolutely zero metal shavings.

Maybe YOU had a bad diff but if you did even a little bit of research, you would see that differentials can be clunk, especially the M sport differentials. It does not mean the diff is faulty

Furthermore, your snarky reply to smeal4128 to "read the thread" is ironic because if you read their post, it indicates that they are hearing clunk when coming to a stop, not when pressing the accelerator from a stop.

[Ramos]

Originally Posted by aidanmurphy

The motor mounts are a key point of security for the drivetrain, having collapsed motor mounts will allow extra play and for slack in the driveline to "catch up" causing a clunking noise. This could indeed be felt from underneath the car and could seem like it is coming from the diff area.

I am simply stating that I had the clunk when accelerating with the wheel turned and after changing the motor mounts, I no longer have it. I had also replaced my diff fluid at 50k and had absolutely zero metal shavings.

Maybe YOU had a bad diff but if you did even a little bit of research, you would see that differentials can be clunk, especially the M sport differentials. It does not mean the diff is faulty

Furthermore, your snarky reply to smeal4128 to "read the thread" is ironic because if you read their post, it indicates that they are hearing clunk when coming to a stop, not when pressing the accelerator from a stop.

I would argue that almost everyone on this thread who is having this Thump / Clunk noise has a bad Diff like me.
This is a common issue with the 2020's and I am definitely not the only one with it.
If anything, I would almost guarantee that YOU are the one in the minority with a one off issue that has nothing to do with anyone else here.

How do I know this? well, collapsed motors mounts like what you describe you had would cause constant and massive vibrations, it would be very hard to miss. Also the "play" and the clunks would happen all the time, and would not go away when the car warms up like all of us are describing.

In any case, bad motor mounts are very simple to diagnose, so it doesn't hurt to check for that, but once again, do not come in here trying to pretend that you have the answer when you don't. What we are all experiencing is a Diff issue, and has nothing to do with motor mounts.

[aidanmurphy]

There is no reason to be so hostile! I am just adding my experiences to the thread for others because it is an easy thing to check

Even if changing the diff resolved the clunk, I am not sure if they were "bad" to begin with. Could just be the preload is out of spec causing the noise, not necessarily a dangerous condition that will lead to a diff grenading

[Ramos]

Originally Posted by aidanmurphy

There is no reason to be so hostile! I am just adding my experiences to the thread for others because it is an easy thing to check

Even if changing the diff resolved the clunk, I am not sure if they were "bad" to begin with. Could just be the preload is out of spec causing the noise, not necessarily a dangerous condition that will lead to a diff grenading

No one is being hostile.
You just started discrediting others including myself who know for a fact that the noise is coming from the diff.

I don't know of anyone where this issue has led to something worse or for the diff to blow up, but I didn't want to take that chance, especially when the car was still under warranty.
An out of spec preload is a faulty Diff since I do not think BMW centers are able or even allowed to open up the Diffs to try and correct the issue.