[CuntFace5000]

Hello,

Had my 335d xdrive in for an engine oil change today and they noticed a significant oil leak from what looks like the transfer box.

They said further investigation was needed, however I now have a third party warranty so I can't use main dealers to carry out the work. I will have to get an independent specialist to diagnose and repair.

The car has only done 27,000 miles. The BMW dealer said it was very unusual for an oil leak like this with a low mileage car. They also said 9 times out of 10 it is just a seal.

What worries me though is if there is a reason for the seal failing like a worn shaft, splines or a bearing on it's way out.

The reason I'm worried is because thinking about it when at cruising speeds, say a steady 70mph, there would sometimes be a low frequency droning noise that would come and go. The noise would build up to it's peak (which wasn't very loud) then get quieter then within a second or so the noise would cycle again. Say 1 cycle of noise every 2 seconds.

I am hoping it is just a seal that needs replacing and that the noise was unrelated. However my gut tells me there is an expensive repair bill heading my way.

I would be grateful if anyone who has had, or knows of, a similar issue could share their experience.

[CuntFace5000]

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[CuntFace5000]

2nd picture

[CuntFace5000]

3rd picture, sorry about the picture quality had to take a photo of my laptop screen

[AlpineX]

Originally Posted by demc1982

The car has only done 27,000 miles. The BMW dealer said it was very unusual for an oil leak like this with a low mileage car. They also said 9 times out of 10 it is just a seal.

What worries me though is if there is a reason for the seal failing like a worn shaft, splines or a bearing on it's way out.

In my limited experience the rear diff leaks before the tcase.
It can only really be a seal, or external damage. Get it fixed before something breaks

[Enabled]

When mine leaked it was the splines. I was getting ready to do the seal, but then noticed wobbly output flange for rear driveshaft.

[CuntFace5000]

Originally Posted by Enabled

When mine leaked it was the splines. I was getting ready to do the seal, but then noticed wobbly output flange for rear driveshaft.

I did search this forum and found a detailed post regarding a similar failure.

I do hope it's just a seal.

[CuntFace5000]

Originally Posted by Enabled

When mine leaked it was the splines. I was getting ready to do the seal, but then noticed wobbly output flange for rear driveshaft.

Haha, just realized it was your post

[Enabled]

Mine had a leak mostly at the back though.

A good visual inspection will determine where it's from.