Hi all, my 3 series bmw has an auto gearbox and as its sealed unit how do i know how much oil is in it? Ive been told it could be the o ring or transmission lines..

hi. if its a plastic sump on the gearbox then they do tend to leak out from the seal. best to clean it up then see where its leaking from.

may be a picture of the leak can help here >

there is a drain plug & refill plug for the oil but if you got a leak then topping it up wont last long as would leak out again

Run the car up to operating temp and then take the level plug out ( Allan key screw but can't remember the size ).

No oil should come out but use a piece of paper and check where the oil level is at. If it not near the level plug hole then top up. Then clean the suspected leak area and drive then recheck the leak

Hi Guys,

Thanks for replying.. Im taking my BMW to a gearbox specialist garage on Monday as they say it's not the gearbox leaking its more than likely to be the oil cooler that's leaking which is a common problem on a Bmw