[16BMW235]

Anyone have experience with a leaking differential seal on a low mileage M235i? I have less than 40k and have a leak. Is this normal?

[overcoil]

Mine definitely has a slight seep (2015 and tech noticed somewhere in the 40-50-thousand mile range)
Had car in dealer on Monday (54,000 miles) and the tech didn't list it as an issue.

[Nsing22]

My 2016 was leaking in October of 2021. It was close to 90k miles for me but a similar amount of time from new.

[16BMW235]

Thanks for responses. I am not a mechanic but it just doesn't seem right for such low mileage - maybe that is issue? Maybe not enough driving is not keeping fluid moving to lubricate seals and they are losing their expected life. Again, I am not a mechanic. Just a concerned BMW Owner who doesn't want this to be the start of more and expensive repairs. I am having seals replaced. This will put my mind at ease for now but not my wallet.

[ggggbmw]

I added the MPerf LSD, which is essentially the same case and pinion as the stock. At the 3 year mark, and about 25K miles, it's seeping from the pinion.

Talking with some BMW techs I trust (track day guys), apparently it's rather common. Doesn't affect all units, but a significant percentage.

At this point it's really minor on mine. I'm keeping an eye on the level, and just cleaning it off. Not in any rush to fix as it's not cheap.

[droptables]

Had a rear differential leak on my 2016 m235i XDrive about a year ago at ~63,000km (~40,000 miles). CPO Powertrain warranty replaced left and right rear diff axle seal and all was well.

[designatedposter]

my front seal on the diff has been wet the whole time i owned the car since 30k miles. im at 70k miles and hasnt ever dripped onto the ground. when i change my diff fluid, i do not notice any lost of fluid.

i suggest you open up the fill plug and see if you can gauge how much fluid is in there. better yet, change your fluid and note how much comes out vs how much you put in.

i should note that bmw tech listed this as 'severe' leak, to which i opened up the fill plug and fluid was dripping out. obviously none has dripped in the 10k miles since last fluid change.

i think its a 14mm hex to open it up

[Pr0ximity]

I recently purchased a 2015 M235i XDrive with 37K miles on it. I took it to an independent BMW performance shop (Bavarian Performance Shop in MA) for a "Post Purchase Inspection" since I bought the vehicle from Carvana and this is my first foray into the BMW world (which was long overdue!)

They found that the rear differential main seal was "leaking" which when I looked at it on the lift, was far closer to the "seal weeping" which seems to be a very common situation in these cars.

They ended up submitting the leaking seal, along with a low-performing OEM battery and lack of coolant flush according to required maintenance (time, not miles). Carvana's third-party warranty ended up covering the entire bill using fresh OEM BMW parts.

Long story short though, when they replaced all the differential seals, bolts, and fluid - they didn't discover any significant measurable loss of differential fluid. So as others have noted it seems to be a pretty common discovery on these cars but seems to be relatively harmless.

I hope you got everything sorted out!