Transfer case leak?

[insanesam]

Hi All

I have a 2012 BMW X6 M50D with 50000km on it. Recently noticed some oily residue on the cross member holding up the transfer case. The residue did not have any smell to it. Upon closer inspection the transfer case was bone dry (I especially checked around the shaft seals, actuator motor and fill plug). I wiped the the cross member with brake clean. A week later the residue came back and I checked the transfer case again which was bone dry. Picture attached. Anyone can explain where this residue is coming from or what it is?

Thanks,
Sam

IMG_20190816_190528.jpg (145.18 KiB) Viewed 18067 times

[mr angry]

You say you checked the fill plug but did you also check the drain plug?

[insanesam]

There's no drain plug on this transfer case

[X5Sport]

This data from the BMW Tech Instr may help? Newtis is a copy of the official BMW Dealer used maintenance & repair guide.

https://www.newtis.info/tisv2/a/en/e71- ... nsfer-box/

[mr angry]

There's no drain plug on this transfer case

Ah ok...my 2010 40d has fill and drain plugs

[insanesam]

Yep already went through the newtis / realoem sites to see if there was anything obvious. My transfer case is the ATC45L which only has a fill plug.

[X5Sport]

Found this ‘exploded’ drawing which might offer a clue?

http://jpat.co.uk/uploads/1/0/3/5/10354 ... atc45l.pdf

It not having any smell is a puzzle as that often means water. Odd place for it and an odd colour/consistency (which is very oil like) unless there is a drain for something nearby? Body wax that’s got hot maybe?

[marti]

Looks from the pic to be oil rather than fluid?

[X5Sport]

I have a picture of the underside of the X6 and that looks to be close to the gearbox/transfer box join (assuming front is to the left?). Hard to tell because of all the covers etc BMW have installed under the X6 models.

Have you had the car in the air and the underbody shielding off?

There are also two vent pipes that come off the top of the ATC45L and seem to sit just above that area. Could it be from there?

[insanesam]

I have a picture of the underside of the X6 and that looks to be close to the gearbox/transfer box join (assuming front is to the left?). Hard to tell because of all the covers etc BMW have installed under the X6 models.

Have you had the car in the air and the underbody shielding off?

There are also two vent pipes that come off the top of the ATC45L and seem to sit just above that area. Could it be from there?

Thanks for the response. In my picture the left of the pic is the rear. I've had the shield rear of the TC removed and could not see anything.
However the the vent pipes sound logical as they sit just above that position. Will check again. Is it normal to have some residue coming out from vent pipes?

[insanesam]

Rechecked everything. Cross member still has the residue. Everywhere on TC is dry. checked vent hose also dry. Very baffling. Does anyone know where the AC evaporator hose thing is?

[Horizon]

For piece of mind I would get the levels checked on all my fluid levels.
On a lighter note in the eighties, ( before any environmental worries ) we used to take our , Ford Cortina/ Holman avengers/ Moriss Marinas to our local garage, for them to spray used engine oil on to the underneath/ chassis to prevent corrosion, cheaper to the" Zebart " that BL were pushing at the time.
Bloody annoying leaks, but very concerning when you cand identify where from.

[X5Sport]

It could also be the gearbox vent tube which is in that area.

Have a look at newtis.info (BMW Service Manual copy) on line. Realoem may help identify the parts too. You just need the last 7 of your VIN to pull up the right model.

The a/c drain falls into the front prop-shaft rear UJ - hence BMW having to replace prop-shaft under a recall. Make sure all yours have been done! A main dealer will tell you if any are outstanding on your car.