4L30E trans fluid leak..

[thenjnick]

Hey fellow bimmer lovers. Recently went to do some maintenance under my 318 (fuel filter) and noticed my trans is leaking from the bellhousing - or has been for quite some time by the looks of it. Last time I had her in the shop they told me I needed a new output shaft seal which I would love to do myself but my work schedule will not allow it unfortunately or any other maintenance work sadly..anyway if i remember correctly the output shaft is on the opposite end of my leak towards the driveshaft? Please excuse my limited knowledge if transmissions any advice here is greatly appreciated. Thank you in advance I will include some pictures and a poorly shot video of the leak if I can figure out how to post it lol..

EDIT: the fluid has also been changed within the last year or so and it hasn’t really given me any issues performing.


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[66 6]

That looks like engine oil not transmission fluid. It's probably your pan gasket or rear main oil seal in the engine. Check your engine oil and then check again in 1k miles. If that was tranny fluid your tranny would start having issues. Best you check the tranny fluid as well. There is a specific procedure for checking tranny oil. Read up on it before you attempt it.

[thenjnick]

That looks like engine oil not transmission fluid. It's probably your pan gasket or rear main oil seal in the engine. Check your engine oil and then check again in 1k miles. If that was tranny fluid your tranny would start having issues. Best you check the tranny fluid as well. There is a specific procedure for checking tranny oil. Read up on it before you attempt it.

Thanks for the reply. My pan gasket looks fine, i know for a fact my oil filter housing gasket needs to be done soon. Tranny has been serviced recently by myself, fluid looks okay and the level doesn’t seem to be going anywhere(checked at the correct operating temp). Ill look into the rear main seal situation..


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