Rear Diff Leak (2020 M340i xDrive)

cyam · 05-16-2022, 11:57 PM

I have been told by dealership its a leaking gasket and they are ordering parts to fix it under warranty. That's certainly different to the solutions mentioned here, but we'll see what they discover and do when they actually go to "fix" it.

Quote:

Originally Posted by cyam

Yes - have a 2020 M340i about 20,000kms on it and I have noticed some drops of oil under the rear diff. I have it scheduled for dealer to inspect/fix next week.

I am unaware of any ECU flashes/upgrades, I had the car serviced last week and they said no software upgrades were needed. Mind you I have only had the car a couple of weeks. It was due a service which was of no charge to me. They should have noticed the diff leak IMO.

Will let you know what they say after I bring it in.

xnick101 · 07-29-2022, 03:56 PM

Going back to the dealer next week for this issue. My diff is starting to make noise now under load. Probably because it's low on fluid and they won't replace it. I will update what the outcome is. This is visit #4 for the same diff leak issue.

xnick101 · 08-04-2022, 09:22 AM

Update: BMW is FINALLY doing something. They ordered a new diff cover to see if it will resolve the leak as it's coming from the breather ports and the drain/fill plugs are dry. No dealer in the US had one in stock is what they said so they ordered it straight from Germany. They said to bring the car back in 3 weeks when they get the part in stock. But in the meantime, they topped off the diff fluid.

baturbo · 10-19-2022, 03:09 PM

Quote:

Originally Posted by xnick101

Update: BMW is FINALLY doing something. They ordered a new diff cover to see if it will resolve the leak as it's coming from the breather ports and the drain/fill plugs are dry. No dealer in the US had one in stock is what they said so they ordered it straight from Germany. They said to bring the car back in 3 weeks when they get the part in stock. But in the meantime, they topped off the diff fluid.

How did you go? Did this stop the leek? Mine was done yesterday and I hoping this will fix the issue.

xnick101 · 10-19-2022, 03:50 PM

Quote:

Originally Posted by baturbo

How did you go? Did this stop the leek? Mine was done yesterday and I hoping this will fix the issue.

Yes, it has completely stopped leaking fluid after they replaced the diff cover!

viciousmo · 11-02-2022, 05:58 AM

Quote:

Originally Posted by xnick101

Yes, it has completely stopped leaking fluid after they replaced the diff cover!

Hey nick, do you have the part # from the work?

bimmerstar · 11-17-2022, 09:14 PM

any update to this thread? My diff is leaking. same issue as everyone else. is there a TSB?

G30M · 11-18-2022, 11:54 AM

does that mean that if one's diff is not leaking not to touch it?

i was thinking of changing diff oil at 5000 miles

xnick101 · 11-22-2022, 06:03 PM

Quote:

Originally Posted by viciousmo

Hey nick, do you have the part # from the work?

This is everything from the work order

xnick101 · 11-22-2022, 06:05 PM

Quote:

Originally Posted by bimmerstar

any update to this thread? My diff is leaking. same issue as everyone else. is there a TSB?

Go to the dealer and show them. There is no TSB as far as I can see but it's blowing oil out of the top breather holes on the diff cover. Replacing it with the newer super-seeded diff cover is definitely the fix. I have had zero leaks after it was replaced.

xnick101 · 11-22-2022, 06:06 PM

Quote:

Originally Posted by G99M5

does that mean that if one's diff is not leaking not to touch it?

i was thinking of changing diff oil at 5000 miles

You can change the fluid. The leak is not from the drain/fill plug.

bimmerstar · 11-22-2022, 07:05 PM

Quote:

Originally Posted by xnick101

Go to the dealer and show them. There is no TSB as far as I can see but it's blowing oil out of the top breather holes on the diff cover. Replacing it with the newer super-seeded diff cover is definitely the fix. I have had zero leaks after it was replaced.

did they replace just the cover or the vent assembly as well? and drain plug?

xnick101 · 11-22-2022, 07:09 PM

Quote:

Originally Posted by bimmerstar

did they replace just the cover or the vent assembly as well? and drain plug?

I am pretty sure the vent assembly is on the diff cover, it goes along the top. They originally replaced only my drain plug and it was still leaking. They replaced it again I believe when they changed the diff cover.

shawntech · 11-29-2022, 11:00 PM

I provided the solve and workup. My car was the test mule and it is still operating correctly.

panki_86 · 11-30-2022, 12:08 AM

I was yesterday at dealership for diff leak. BMW have PuMA document for M340i diff leak and solution is to change diff cover

bimmerstar · 11-30-2022, 07:38 PM

Quote:

Originally Posted by panki_86

I was yesterday at dealership for diff leak. BMW have PuMA document for M340i diff leak and solution is to change diff cover

please provide details. doc number, pic of doc etc.

RLYSLO · 12-01-2022, 07:55 PM

Quote:

Originally Posted by panki_86

I was yesterday at dealership for diff leak. BMW have PuMA document for M340i diff leak and solution is to change diff cover

Same, I went for an inslection service this morning and asked them to look at the diff. Confirmed breather issue and is booked for two weeks time to replace rear diff cover.

Also got flagged for tuned DME but they were cool as about it and asked what I was planning on doing mods wise.

panki_86 · 12-01-2022, 11:52 PM

Quote:

Originally Posted by bimmerstar

please provide details. doc number, pic of doc etc.

I didn't took a pic or doc number, but i saw PuMA at dealership PC.
This PuMA is from 2021.

bimmerstar · 12-02-2022, 08:24 AM

Quote:

Originally Posted by RLYSLO

Same, I went for an inslection service this morning and asked them to look at the diff. Confirmed breather issue and is booked for two weeks time to replace rear diff cover.

Also got flagged for tuned DME but they were cool as about it and asked what I was planning on doing mods wise.

can you please grab a copy of paper work or anything to show bmw covers the leak

thanks.

RLYSLO · 12-12-2022, 03:05 AM

Quote:

Originally Posted by bimmerstar

can you please grab a copy of paper work or anything to show bmw covers the leak

thanks.

Will do, I just dropped it off then. Will pick it up tomorrow afternoon hopefully.

hayko_M340 · 12-21-2022, 01:57 AM

Is everyone who is facing this issue Xdrive? RWD here and noticed my diff cover oily/grimy and possibly a drop or two on the ground. Right at about 40K miles. Wonder if there is a TSB for RWD models.

xnick101 · 12-21-2022, 01:33 PM

Quote:

Originally Posted by hayko_M340

Is everyone who is facing this issue Xdrive? RWD here and noticed my diff cover oily/grimy and possibly a drop or two on the ground. Right at about 40K miles. Wonder if there is a TSB for RWD models.

There is no TSB. It's an issue on M340i's and Supra's. It's due to the design of the breather holes on the top of the diff. I have a RWD M340i and BMW replaced my diff cover under warranty and it does not leak anymore.

07-29-2022, 03:56 PM	#46
xnick101 Captain 651 Rep 818 Posts Drives: 2021 BMW X3 M Join Date: Oct 2019 Location: Florida iTrader: (0) Garage List 2020 BMW M340i [0.00]	Going back to the dealer next week for this issue. My diff is starting to make noise now under load. Probably because it's low on fluid and they won't replace it. I will update what the outcome is. This is visit #4 for the same diff leak issue. __________________ 2014 BMW 335i M-Sport - SOLD 2020 BMW M340i - SOLD 2021 BMW X3M
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08-04-2022, 09:22 AM	#47
xnick101 Captain 651 Rep 818 Posts Drives: 2021 BMW X3 M Join Date: Oct 2019 Location: Florida iTrader: (0) Garage List 2020 BMW M340i [0.00]	Update: BMW is FINALLY doing something. They ordered a new diff cover to see if it will resolve the leak as it's coming from the breather ports and the drain/fill plugs are dry. No dealer in the US had one in stock is what they said so they ordered it straight from Germany. They said to bring the car back in 3 weeks when they get the part in stock. But in the meantime, they topped off the diff fluid. __________________ 2014 BMW 335i M-Sport - SOLD 2020 BMW M340i - SOLD 2021 BMW X3M
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11-17-2022, 09:14 PM	#51
bimmerstar Second Lieutenant 149 Rep 235 Posts Drives: 2020 BMW M340xi Join Date: Aug 2022 Location: Michigan iTrader: (1)	any update to this thread? My diff is leaking. same issue as everyone else. is there a TSB? __________________ 2024 G87 Zandvoort Blue M2 w/ Buckets - Stock 93\| 0-60 TBD \| 1/4 TBD \| 60-130 TBD 2020 G20 Tanzanite Blue II M340 xDrive - E30 BM3\| 0-60 3.28 \| 1/4 11.39@123 \| 60-130 9.56 Past: 2017 W205 Black C43 AMG - E40 FBO No Turbo \| 0-60 3.21 \| 1/4 11.18@124 \| 60-130 9.17
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11-18-2022, 11:54 AM	#52
G30M Brigadier General 3787 Rep 4,143 Posts Drives: BMW M550i; Kia EV6 GT Join Date: Dec 2021 Location: Australasia iTrader: (0)	does that mean that if one's diff is not leaking not to touch it? i was thinking of changing diff oil at 5000 miles
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11-29-2022, 11:00 PM	#58
shawntech The Wolf 247 Rep 987 Posts Drives: stuff Join Date: Oct 2013 Location: Midwest iTrader: (0) Garage List [0.00] 2019 BMW M850i conv ... [0.00]	I provided the solve and workup. My car was the test mule and it is still operating correctly.
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11-30-2022, 12:08 AM	#59
panki_86 Private First Class 112 Rep 187 Posts Drives: G20 M340i xDrive Individual Join Date: Aug 2021 Location: Slovenia iTrader: (0)	I was yesterday at dealership for diff leak. BMW have PuMA document for M340i diff leak and solution is to change diff cover
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12-21-2022, 01:57 AM	#65
hayko_M340 Second Lieutenant 139 Rep 238 Posts Drives: 2020 BMW M340I Join Date: Jul 2016 Location: California iTrader: (0)	Is everyone who is facing this issue Xdrive? RWD here and noticed my diff cover oily/grimy and possibly a drop or two on the ground. Right at about 40K miles. Wonder if there is a TSB for RWD models.
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