BMW Front Differential Failing?

[m240.to]

Hey everyone, hope you're all doing well! I just joined the forum and would like to bring something to your attention.

I wanted to share an experience I had with my 2022 BMW M240i. At 10,000 km, I decided to drain the entire drivetrain, including the transfer case, transmission, and rear differential. Given that the rear diff is very similar to those in M cars, I figured it wouldn’t hurt to change the oil despite BMW’s recommendation to the contrary, as well as my peers in other BMW related groups.

When I first drained everything, the oil was quite dirty with a noticeable amount of break-in contamination. The oil analysis report indicated new unit wear, but after the initial change, everything has been running smoothly, the oil analysis are coming back normal, and I'm glad I made that decision.

However, I'm now facing an issue with the front differential. I've included some comparisons below for reference (my rear diff), and it seems like there might be a serious problem with the front diff. My car is usually driven with DSC fully off, so the front diff doesn't get much use (this car is 80-20 biased, x-drive), which makes this even more puzzling.

There's a minor clacking noise coming from the front area of the car, and I'm not sure what to do next. Should I consider taking the diff apart to inspect it? This is a labor-intensive job, and even outside of BMW, it would cost me a couple of grand in labor.
I’d really appreciate any insights or advice from the community. Thanks!

 

[Reggaemon]

Hi, I'll just say "Welcome" and toss this one to our many BMW experts.

 

[Cujet]

Seems like a warranty concern. If fluid changes are forbidden, don't mention it.

 

[m240.to]

Seems like a warranty concern. If fluid changes are forbidden, don't mention it.

The fluid in my M240, like all BMWs, is considered "lifetime," but I’m skeptical of that claim, especially for gear oil. Keeping a gear oiI in for the "lifetime" of the car is stupid, and no such thing exists… every single member here would surely agree with me. Anyways, I thought about showing the oil analysis reports to prove something is wrong, but I'm worried BMW might use it against me. They could argue that I did the fluid changes because I drove the car hard, changed the fluid preventively, and broke something as a result of driving the car hard, then tried to get a warranty repair. At BMW’s labor rates, this could easily become a CAD$10,000 repair, even though I could get it done elsewhere for a fraction of the cost, maybe a little more than a quarter. BMW NA isn't as lenient as it used to be, and they might look for any excuse to void the warranty.

If I don’t show the oil analysis reports, I’ll need to change the fluid for a third time at my shop. Both the fill and drain plugs have magnetic plugs, so I would need to put the old ones back in to cover my tracks.

The pan is also upgraded, and although it utilizes original BMW parts, it is original to a BMW M5 Competition. To swap that out as well would add to the cost (all BMW ZF8speed pans are interchangeable, you just have reduced clearance as a result for that specific pan). It's a double edged sword because it is completely un-related to the part where the "failure" occurred, and should hold no bearing in a warranty case… but the techs will notice that and that suggests I've touched the drivetrain of the car… at least the transmission...

While on the topic of "driving the car hard", logically, that argument would have zero basis. If it was due to that, you would see it in the rest of the drivetrain, not an isolated issue in the front diff like this one. BMW however does not give a cr*p about logic, so what I think is logical will not hold up in a warranty case, even if it is.

 

[fantastic]

Agree w/ @Cujet to get it looked at under your warranty. Lifetime fluid doesn't change the fact there is a noise & a sample that shows very high wear going on. I'd not mention the change & push warranty to do an oil analysis if they don't want to mess with it. That will prove to them something more is going on for them to dig deeper into the front end.

 

[m240.to]

Agree w/ @Cujet to get it looked at under your warranty. Lifetime fluid doesn't change the fact there is a noise & a sample that shows very high wear going on. I'd not mention the change & push warranty to do an oil analysis if they don't want to mess with it. That will prove to them something more is going on for them to dig deeper into the front end.

The noise is very little and is not easily noticeable unless you are like me and drive this car frequently, and you are very in tune when something feels off. And no, I am not confusing it with injector tick, I am aware of the infamous injectors on the B58TU engine.

I can only hear it under certain circumstances, not entirely sure what those are at the moment. Perhaps it can be heard from the outside, but my dad has left the country and he is the only other person that I would trust to help me with this issue. I would have to wait till he comes back before I can do anything with regards to BMW.

 

[SubieRubyRoo]

Hey everyone, hope you're all doing well! I just joined the forum and would like to bring something to your attention.

I wanted to share an experience I had with my 2022 BMW M240i. At 10,000 km, I decided to drain the entire drivetrain, including the transfer case, transmission, and rear differential. Given that the rear diff is very similar to those in M cars, I figured it wouldn’t hurt to change the oil despite BMW’s recommendation to the contrary, as well as my peers in other BMW related groups.

When I first drained everything, the oil was quite dirty with a noticeable amount of break-in contamination. The oil analysis report indicated new unit wear, but after the initial change, everything has been running smoothly, the oil analysis are coming back normal, and I'm glad I made that decision.

However, I'm now facing an issue with the front differential. I've included some comparisons below for reference (my rear diff), and it seems like there might be a serious problem with the front diff. My car is usually driven with DSC fully off, so the front diff doesn't get much use (this car is 80-20 biased, x-drive), which makes this even more puzzling.

There's a minor clacking noise coming from the front area of the car, and I'm not sure what to do next. Should I consider taking the diff apart to inspect it? This is a labor-intensive job, and even outside of BMW, it would cost me a couple of grand in labor.
I’d really appreciate any insights or advice from the community. Thanks!



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Question, did you use OEM BMW diff fluid or something else? Just wondering because there was another thread on here with a failed BMW front diff but they never said what fluid they used (or if it failed because a tech drained it and forgot to refill it).

But I agree with your decision to swap it out, and to not mention that when you take it in to have it looked at.

 

[m240.to]

Question, did you use OEM BMW diff fluid or something else? Just wondering because there was another thread on here with a failed BMW front diff but they never said what fluid they used (or if it failed because a tech drained it and forgot to refill it).

But I agree with your decision to swap it out, and to not mention that when you take it in to have it looked at.

I always use original BMW fluids for my BMWs because these components are highly sensitive to anything that's not BMW OE. I've seen people use RedLine diff oil in these diffs, and I completely disagree with that approach. A handful of people I know have developed issues with it.

The only part of my car that doesn't use original BMW fluid is the engine. It runs on RedLine High-Performance ES 5W30, which meets/exceeds the BMW LL04 spec. BMW LL04 is approved in Europe for this car, but not here in North America due to high sulfur and ethanol content in the gas. Consequently, I have to keep my drain intervals short. This oil adheres to the low SAPS formula, which is recommended to prevent LSPI (low-speed pre-ignition). While LSPI might not be a significant concern for a 3.0L engine, I've seen a few German videos on B58 engine tear-downs due to LSPI failure. My UOAs are perfect, so I see no reason to change what I'm currently using (compared to original BMW 0W20, which wasn't so perfect).

For everything else, I stick to BMW OE fluids: the rear diff uses BMW GL4, the front diff uses BMW GL5, the transfer case uses BMW DTF1, and the transmission originally had ATF3, which I swapped for ZF LF8. All sources claim it's the same re-branded fluid, and after testing both VOAs, I can confirm that's true. So no reason to pay 6x the price on BMW branded transmission fluid.

 

[m240.to]

But I agree with your decision to swap it out, and to not mention that when you take it in to have it looked at.

Thanks for the feedback.

I've faced a lot of criticism in the BMW groups I'm part of for wanting to service the drivetrain on my car, which sees a fair amount of spirited driving on backroads. They insisted that my car is a "fake M" (which, technically, it is) and therefore doesn't require a differential service like a real M car.

This logic didn't make sense to me, especially considering the ELSD (electronic limited-slip differential) in the M-Performance cars and M cars of the G chassis generation are very similar - almost the same. The numerous oil analysis reports I’ve collected, both used and baseline, clearly prove them wrong.

It's frustrating because I've taken so many precautions to maintain a car that means a lot to me, and now something might be prematurely failing, even if it's not my fault and the car is a lemon.

 

[wavinwayne]

As others have said, I would have BMW look at it as a warranty concern. I also agree that I would not say anything about the fluid change, because IMO they WILL use it against you.

 

[dubber09]

Did you use BMW fluids or 'comparable'?
BMWs are sensitive to fluids, my buddy auto mechanic never used anything but BMW fluids (except oil) in those cars.

 

[SubieRubyRoo]

Thanks for the feedback.

I've faced a lot of criticism in the BMW groups I'm part of for wanting to service the drivetrain on my car, which sees a fair amount of spirited driving on backroads. They insisted that my car is a "fake M" (which, technically, it is) and therefore doesn't require a differential service like a real M car.

This logic didn't make sense to me, especially considering the ELSD (electronic limited-slip differential) in the M-Performance cars and M cars of the G chassis generation are very similar - almost the same. The numerous oil analysis reports I’ve collected, both used and baseline, clearly prove them wrong.

It's frustrating because I've taken so many precautions to maintain a car that means a lot to me, and now something might be prematurely failing, even if it's not my fault and the car is a lemon.

I’m not disagreeing with you on any of what’s happened so far, but I find it highly suspicious that BMW diffs are “so special” that a normal GL4/GL5 rated fluid would cause issues.

I suspect, purely on anecdotal evidence at this point since I don’t concern myself with BMW message boards, that BMW probably has a high failure rate all around with their front diffs and simply does their best to silence any dissension in the ranks (“We’ll cover your diff failure under warranty, but only if you sign an NDA” kind of stuff). It’s pure speculation, but if you swapped out the fluid at 6k miles with OEM fluid and are having a legit failure, you’re not the outlier- you’re in the meat of the bell curve.

If you’re so inclined, PM me after reading my “Mega 75w90 Test” thread if you’re willing to send a new quart of the fluid you used for testing. I can probably pull some strings and get a full set of tests done on it like was in the thread. I think it’s quite odd that 98% of all differentials will usually last cradle-to-grave without ever changing the fluid, and BMW seems to have a significantly higher rate of failure.

 

[m240.to]

Did you use BMW fluids or 'comparable'?
BMWs are sensitive to fluids, my buddy auto mechanic never used anything but BMW fluids (except oil) in those cars.

I mentioned above that I only use BMW original fluids.

 

[m240.to]

I’m not disagreeing with you on any of what’s happened so far, but I find it highly suspicious that BMW diffs are “so special” that a normal GL4/GL5 rated fluid would cause issues.

I suspect, purely on anecdotal evidence at this point since I don’t concern myself with BMW message boards, that BMW probably has a high failure rate all around with their front diffs and simply does their best to silence any dissension in the ranks (“We’ll cover your diff failure under warranty, but only if you sign an NDA” kind of stuff). It’s pure speculation, but if you swapped out the fluid at 6k miles with OEM fluid and are having a legit failure, you’re not the outlier- you’re in the meat of the bell curve.

If you’re so inclined, PM me after reading my “Mega 75w90 Test” thread if you’re willing to send a new quart of the fluid you used for testing. I can probably pull some strings and get a full set of tests done on it like was in the thread. I think it’s quite odd that 98% of all differentials will usually last cradle-to-grave without ever changing the fluid, and BMW seems to have a significantly higher rate of failure.

I did some research and found that while front diff failures in BMWs are not very common, they do occur. Many of these failures seem to happen on the X5 G05 (same generation as my M240) SUVs, which use the same front diff system.

Several people who experienced these issues were quoted multi-thousand dollar repair bills. Some managed to get the repairs covered under warranty, while others did not.

From what I can tell in my situation, this looks like more than just wear and tear—it appears to be a failure that's already occurred and will get worse and worse. When a complete failure happens, it can occur at any time and will be unpredictable? I'm fairly certain this will require a full replacement since BMW dealerships do not "rebuild" differentials. Unfortunately, in Canada, we don't have specialized shops for this kind of work… in the US? Probably.

My best course of action seems to be to remove the magnetic plugs from the diffs, replace them with non-magnetic versions, and take the car to BMW, hoping for the best.

 

[chris719]

This logic didn't make sense to me, especially considering the ELSD (electronic limited-slip differential) in the M-Performance cars and M cars of the G chassis generation are very similar - almost the same. The numerous oil analysis reports I’ve collected, both used and baseline, clearly prove them wrong.

I'm not going to dispute your data, but the LSDs are not the same. I've seen both off the car. They may be the same type of LSD but who knows what is different internally and I'm not even sure the vendor is the same. The M units are derivatives of the GKN that came on the F90 M5.

With your front diff, you have probably set yourself up for a tough situation. I'd make it look like you never changed fluids and drive until it fails unless you're good buddies with your SA. Unless you can demonstrate a problem like noises you'll just make them suspicious and think you're crazy if you tell them you had elevated wear metals.

 

[chris719]

If you’re so inclined, PM me after reading my “Mega 75w90 Test” thread if you’re willing to send a new quart of the fluid you used for testing. I can probably pull some strings and get a full set of tests done on it like was in the thread. I think it’s quite odd that 98% of all differentials will usually last cradle-to-grave without ever changing the fluid, and BMW seems to have a significantly higher rate of failure.

I don't know what's special but those electronically controlled clutch pack type diffs that BMW sources from GKN for the M cars seem to be a bit fickle. The non-M cars almost never have failures but the M cars have frequent failures when the dealer uses the wrong fluid (either with FM or the open diff fluid) in them, could be friction modifier related. The OE fluid in North America is Castrol SAF-XJ 75W-140 (w/o FM boost) that is discontinued but Castrol produces for BMW still and some unknown Shell product MSP/A in ROW. I'm pretty sure that they would be fine with a comparable fluid. At least one forum member tracks his with Motul Gear Competition 75W-140 and it hasn't had an issue yet.

OPs is not the same diff, doesn't take the same fluid, and doesn't have a track record of as many failures with different fluids so who knows.

btw that thread of yours is one of the real gems on this site

 

[RAVL]

This car is a ‘22? Is it not still under warranty? If it is under warranty, I would stop monkeying with it and bring it to the dealer. My experience is that BMW and the dealer network behave honorably with warranty claims, and if there is an issue they will fix it. The more you do here, the more of a question you may raise as to whether it can be covered. Good luck with it.

PS: do yourself a favor and stay off of the BMW forums — I see you did some “research” — that generally means the Internet forums. ;-) I have driven BMWs since 1990. (Raced and auto crossed too.). They are great cars but like anything else there are issues. Internet forums, particularly the BMW ones, completely blow these issues out of proportion in my experience and wind up ruining your experience with what are generally great cars. Mike Miller of Roundel is another drama queen, albeit a knowledgeable drama queen. Are they expensive when they break? Yes, but those risks can be mitigated with a factory extended warranty and, not to sound like a jerk, if the money is that dear folks shouldn’t be messing with German luxury sport cars. Plus, if you are handy you can also keep the cost reasonable in that manner as well. Again good luck with the 240, it is a great car. If there is an issue, BMW will make it right, just don’t cloud the issue by messing with it further or not using factory fluid on any driveline component. Take care.

 

[BMWTurboDzl]

This car is a ‘22? Is it not still under warranty? If it is under warranty, I would stop monkeying with it and bring it to the dealer. My experience is that BMW and the dealer network behave honorably with warranty claims, and if there is an issue they will fix it. The more you do here, the more of a question you may raise as to whether it can be covered. Good luck with it.

PS: do yourself a favor and stay off of the BMW forums, I have driven BMWs since 1990. They are great cars but like anything else there are issues. Internet forums, particularly the BMW ones, completely blow these issues out of proportion in my experience and wind up ruining your experience with what are generally great cars. Mike Miller of Roundel is another drama queen, albeit a knowledgeable drama queen. Are they expensive when they break? Yes, but those risks can be mitigated with a factory extended warranty and, not to sound like a jerk, but if the money is that dear folks shouldn’t be messing with German luxury sport cars. Plus, if you are handy you can also keep the cost reasonable in that manner as well. Again good luck with the 240, it is a great car.

+1

OP is in for a surprise if they see tool marks on the front diff.

 

[chris719]

+1

OP is in for a surprise if they see tool marks on the front diff.

I'd buy new plugs if possible and change the fluid carefully .

 

[edyvw]

this car is 80-20 biased, x-drive),

It is 40/60%.
ECU shifts power based on need and driving patters. Even when you turn off DSC torque distribution stays the same.
If you track vehicle, ECU recognizes that and shifts to 20/80%, or sometimes 100% to rear wheels.
Your spirited driving won't do anything unusual to your BMW. Spirited driving is very subjective, and on regular roads, regardless of how much you push it, won't overwhelm vehicle components.
I still don't understand. Do you have any issues? Noise is just that, noise, and it might be coming from some different part of the vehicle. High elevated numbers might be actually normal. Depends on materials used. Some engines have normally high iron numbers, some very low. Same is with differentials.